Pw Enterprise — they are asking for more money or case

Hi, i registered in this company in dec 2018.. After reading the reviews here i decided to quit. They told me to pay 7800 and issued a letter which said due clearance and termination. Today an advocate calls me asking for 3500 more. It was very unpleasant speaking to that man. He was threatening that otherwise by the end of eleven months i would hv to pay 160, 000 as the 11 month salary the company had promised in the letter. I told him my name is terminated in their server as per the agreement clause since i already paid7800and hv the letter with me. He said there’s another letter of case withdrawal that i must get from them to close the agreement. I don’t understand why we get trapped in all this. Kindly, help resolve this case. We can’t waste money and energy on frauds like this. Please, help.