No service no response

I have joined with Isat in December. Firstly the overcharged me and never did a refund and then above all i still haven't been able to use me data as my simcard was not registered. I have sent through the documents again but have had no response. Never do business with these people. They will never get back to you and the call centre is useless aswell. And note that they never respond to anything, not even the bad reviews they get on hellopeter.