I would first file a direct dispute with them over the accuracy of the reported amount of the debt.
First step is always to file a disptue, making them aware of an asserted inaccuracy, and requiring they conduct a reasonable investigation, and providing a determination supported by that investigation.
If they either verify or update, then use FDCPA 808(1) and your original account agreement to evaluate whether it is in compliance.
If not in compliance, I would then either contact the CFPB with a formal complaint of violation of FDCPA 808(1) or inititate your own civil action.
