A Contract Does Not Mean Chargeback Protection
One common misperception when it comes to chargebacks, especially online, is that having a signed contract will protect you from chargebacks. This is mostly untrue. American Express will deny a chargeback if a merchant can provide a signed contract in which the customer acknowledges that the work was completed/product delivered and was satisfactory. However, Visa and MasterCard will not stop the chargeback even with this kind of documentation.
Visa and MasterCard’s stance on this is that they will not be a collection agency for merchants. But this doesn’t mean that you are out of luck on collecting the money you are rightfully owed. A signed contract is still a legal document and will hold up in a court of law. You will probably end up in a slightly protracted dispute but ultimately you will receive your funds.