Dealership not honoring contract?

[biz999]

So here is what is happening to me (I'll fill in with more detail as needed):

I've been looking a for specific used car, I found one in Montreal. I negotiated on the phone, came to an agreement and went to check it out. I brought along a certified cheque for the amount agreed upon with the full intention of buying.

The car had a couple of things that still needed to be fixed, so I decided not to take the car on the spot. Came to an agreement that the items will be fixed, and wrote-up a contract, and put down a deposit for the car. That was 2 weeks ago. I have a signed contract.

Today is the day I was planning on going back. I receive a call from the Sales Manager this morning saying the car cannot be sold for that low, and gave me a counter-offer. I told them I have a signed contract, and have already paid a deposit on it.

What can / should I do?

[mbk.2k3]

utter BS if there is a signed contract, that both parties signed to, agreed to, why the heck can they change the terms?

theres seasoned vets on this RFD forum, i'll let them comment on best course of action.