I was working for a company in Jebel Ali free zone Dubai past one and a half years.My company terminated me just because a competitor offered me a job however I did not except.During Visa cancellation JAFZA asked me to sign a non competition letter which I refused to sign just because my contract was terminated by the company and this clause was never there in the first place in the JAFZA labor contract.The company is threatening to impose a one year immigration or no entry ban on me. Please advise on what grounds can they do that?