What does your contract spell out for material and warranty? Unfortunately this may be the point where you learn a hard lesson and start using contracts with your contractors. Without a contract you have little to no recourse other than to not use them again. If you have a quote that spells out material used you may be able to go after them for that. The contract should be simple but contain the scope, rough cost, payment schedule, material specifications and ramifications of missing deadlines or warranty period. There are plenty of other things you could add to it but it tends to scare away contractors if it gets too long.
You may be able to go after them for breach of contract but only if you have something in writing (contract, quote, receipt with different material than quoted, etc.) but it will cost you as much in legal fees and they do not help you collect even with a judgment.
A licensed contractor is a good direction to start with but even then you still need a solid contract. Anyone that won't sign a reasonable contract is your first red flag. Pay a few bucks more and use a good contractor.