WTF?! How the hell can they not have that sorted out by now? It's not like there was even a problem until they made one.

I'd suggest contacting a customer advocacy site like the consumerist. Hopefully if your story gets posted on there, Valve will take attention to your plight.

I actually find that threatening to write to relevant businesses (including gaming sites and magazines in this case) in a matter of fact tone gets results very quickly.
The difference is in the time it takes for anything you write to be published and responded to.
Just state the situation. Tell them what happened and when. Tell them what you need to happen and by when and what will happen if they fail to resolve the matter.

To be honest at this point I cant be bothered. Steam's support tracker shows the whole sorry affair and how long its taking for the whole business. Last thing I was told was that the banks involved are not talking. Whatever the hell that means. When it finally comes to a conclusion I will summarise it all on a webpage so everyone can have a read and enjoy. If Steam are at fault then I expect to get a least an apology and I mean a proper one.

Ugh. If your issue is tied up by bank bureaucracy, Delixe...yikes. They'll get to sorting that out in their usual 'efficient' fashion, and we all know how quickly financial institutions deal with...well, ANYTHING. :(

The only way Steam can fix its shit is if people actually start taking notice of how much it sucks. Right now it's only within communities that people murmur about it. Look at how many Steam fanbois there are on the Zeno Clash forum the last time I brought up the Impulse thread. It stupefies me how the herd mentality on the Internet is so similar to my country's - and that's quite a feat. The interest in defending a popular product is always greater than the voice of the disgruntled.

What 'shit' does steam need to fix? I love steam, and I've never had a real problem with it. If people don't 'notice how bad it sucks' maybe that's because.... it does not suck.
Maybe the reason there is more interest in defending a popular product is because.... it's popular and most people are happy with it and you are in the minority? Just because you don't like something does not mean it's objectively bad and anyone who disagrees with you is wrong.
Delixe - I have no idea what your problem is (I feel like I'm missing most of the story somewhere) but if the problem is with banks not talking or something.... I don't see how that's really steam/valve's fault and I'm not sure there is anything they could do to speed it along.

They were banned due to an old credit card purchase through Steam allegedly being questioned by the credit card company.
The shit that Steam needs to fix is its ability to ban someone from using their entire account and all the games in it (along with any other accounts they have) at the drop of a hat. They have the ability to temporarily delete and titles that come into question just as they have the ability to block accounts from making further purchases. That should be enough before they have confirmation of any wrongdoing.
That among many other problems, such as its beleaguered offline mode and backups.

Hmm.... that's the only time I've ever heard something like that happening to anyone and it sounds like at the core it was the credit card company's fault not steam's. Steam's concern might be that if he used a stolen credit card ( I'm not accusing him of that, just saying that might be what Steam and/or the credit card company think) then other games on the account may have been purchased with a stolen credit card too or something. I'd have to hear the whole story before I'd condemn Steam for it.
As for offline mode and backups... what's the problem with them? I've used offline mode before and it worked just fine. I've never had a reason to back up my game but I just tested it out and it seemed to work OK.
Edit: Delixe, that does sound a little shady then. I'd love to hear why they would do something like that and I can understand why you would be mad.

Admittedly, I do avoid credit cards for this reason. You're not buying anything. They are and you're paying them to do so. So they've got every right and reason to poke their nose into any and every transaction they see fit.
So, probably from the credit card company's standpoint, it's just business as usual. But it's entirely possible that someone at Steam overreacted to the inquiry and slammed down the ban hammer.
But then that's the real issue: the fact that they can do so with great ease in a way that completely locks people out of their accounts. All compounded by the fact that they're so unable to quickly resolve the matter.
Is there any reason why they cannot delete the offending titles? No. They actually do that. It's not like they're able to remove the files from your drive. Just your ability to use them. So doing that means that any issues can be resolved relatively painlessly.
Equally there's no way I'll accept that they can't stop a person buying games and being gifted to. So, all in all, the present way they handle such situations is unacceptable on just about every level.

Offline is touch and go. Sometimes it works. Sometimes it outright refuses. Backups are actually a part of the problem with offline mode in that you can't restore backups without being online. This is also true of reinstalling boxed copies that have already been activated. The backup process also seems to involve downloading substantial numbers of files also. Which makes you wonder just how much value the backups have.
Oh and if you want to backup to a set amount of discs you can forget it. It's completely hopeless at estimating the amount of discs required. Which means you're left with discs with just a couple of hundred MB on.