LONGRUN FINANCIAL won’t let me withdraw and keeps stalling off.

I met someone on the Internet who claimed to guide others to buy and sell gold. His surname is Liu. We call him Mr. Liu. In August 2018, Liu asked me to go to the LONGRUN FINANCIAL platform to register and deposit and let me use a mobile app called "MetaTrader5" for gold trading operations. Around the beginning of November 2018, Liu said that this trading platform may have problems and let me withdraw all the money in it. At that time, I had about 100,000 RMB in LONGRUN FINANCIAL. I applied for withdrawal from 2018.11.21. The platform said that I can only apply once a day, and I can only apply for a withdrawal of 5,000 US dollars (35,000 RMB) at a time. From the time of applying for the withdrawal, the platform has returned a total of RMB 40,000, and there are still about 63,000 RMB in the platform.