Unauthorized premium deduction

Simply OMART is deducting my money that I do not even know what is it for. I never signed anything with the company. It appears on my payslip even worse. This is the 3rd month they are doing this. Last month they refunded me and gave a cancelation letter that I have been removed from their database. I'm surprised that they did it again this month. Even worse I never authorized anything with them nor talking to them.