Yes of course, the use of multiple accounts and VPNs are the most common ones. Some might also allege you use a cheating system or approach. It may or may not be true judging by my experience in similar cases.

At this point, you are at their mercy and some people were able to get their money back after some back-and-forth messages on their communication channels. But some would have to call them out in forums and other social media platforms to achieve their aim, and to avoid losing trust/reputation, they oblige some.

However, others may hire a lawyer or mediator/arbitrator to mediate in the case.