I think that was the reason why have detected you using multiple account. Most likely they have checked your IP address, and usually it would happened if you had used VPN. Perhaps some other users used same VPN or IP address that you had used. Is it against their terms & conditions? I am not sure about it since I had not read. I don't think they will scam this kind of small amount since they have solve more issue with more big amount. Try to discuss their ANN thread as coinlocket$ already mentioned, hope your problem will solve.