Absolutely not. I agree with the prior poster:
Dear Valued Customer,
I have undertaken the fixes we already agreed to verbally, and they are ready for delivery at such time as I receive the signed copy of the contract already in your possession. If you have misplaced the contract, I can send you a replacement copy. This is for your legal protection, as well as my own. Thank you in advance. I await your transmission of the signed copy of our already agreed to contract, along with your instructions as to the delivery of the already completed work product.
If they have a problem signing the contract, you'll have an even bigger problem receiving payment. Standard best business practice is of course to withhold all work, until such time as they sign the contract.