[ianisakson]

i'm not a lawyer so don't take this advice too seriously

The only way you're in the wrong is if the sheet of paper you signed legally qualifies as a contract. ie it explains what is being exchanged for what price. If it is just a grid with space for names then you're probably in the clear. Also, did you get the t-shirts or not? If you didn't get the t-shirts then obviously they are breaching the so called contract anyways so you owe them nothing. You're probably good here, just call them and ask them to have a lawyer review their so called contract to see if qualifies as legal. Like I said before, i'm not a lawyer and this is not legal advice. I just recommend calling them to clarify whether or not you actually signed a contract.