contract non renewal followed by "offer" of a few extra days

Here's a sticky one for anybody who regularly contracts. I'm in a situation where my contract ends on a fixed date, but the client said verbally that they would be willing to keep me for another week or two. I said that would be great and we would talk again but nothing more was said and nothing was put in writing.

Now the client is pissed because I had assumed that getting nothing more in writing that might or might not happen and I've one of these complex written contracts that stipulates I'm not supposed to go in without having a contract in place and obviously I can't bill the client. I've heard nothing back from my agent since I last spoke to them.

My client is also now grumbling that if I go on that date I'm not giving proper notice, even though really I don't have any proper notice now, aside from not having any kind of job to go to, and nothing concrete in writing to confirm a formal agreement beyond the contract end. Its really difficult, and upsetting enough to have the client get really snotty with me as they had said they couldn't renew me due to the company policy.

Any suggestions or is this really one for proper legal advice. I really feel like I am being shat on as my workload is practically exploding as they try to squeeze every last iota out of me before I go.