The company that sells a service contract may not be the company that stands behind it later. Sellers merge, sell their contract books, change their names, or stop writing new contracts. The assignment and successor language in your contract decides whether a new holder must honor the terms you bought.
Read the assignment clause
Find the sentence that says whether the seller may transfer the contract to another company without your consent, and what notice you receive if it does. Note whether the clause requires the new holder to accept the same terms or leaves that point general. A clause that allows transfer without notice gives you less to rely on than a clause that requires written notice to you.
Read the successor language
Look for a successor clause, which says who takes over the obligations if the seller merges, changes its name, or closes. Check whether the clause covers a sale of the business assets as well as a merger. If the form is silent, ask the seller in writing who will handle claims if it stops doing business.
Check the roster and the state page
A government roster lists who is registered to sell contracts in a state, as of the roster's own as-of date. Use it to see whether a new holder appears, but do not read a listing as a quality rating or a promise of payment. Each state page on this site names the regulator and the statute, and says whether that state publishes a roster. This guide does not summarize any state's rule, so start with the Arizona page if your contract was sold there.
Keep the paper
Keep the original contract, every amendment, and every notice from the seller or from any new holder. Write down the company name on each notice, where it came from, and the day you received it. If the holder changes, file the change notice with the contract so the chain of paper stays complete.