We reverse on cross-appeal the grant of summary judgment to appellant Criterion Corporation. A disputed issue of material fact existed below as to the identity of the term “seller” in the contract clause at issue. The contract specifically identified appellant as the seller, but also set out the “seller’s” duties to be those clearly contemplated to be performed by a third party to the contract.

The contract ambiguity was unresolved, and thus appellant failed to carry its burden *439on motion for summary judgment of proving the nonexistence of any disputed issues of material fact. Snyder v. Cheezem Development Corp., 373 So.2d 719 (Fla. 2d DCA 1979).

REVERSED and REMANDED for further proceedings.