Sim card barred

I have an MTN sim card which I have been using for data for several months and about 3 or 4 days ago MTN decided to bar it, just like that!! No reason, no phone call, they simply barred it, so now I don't have internet access. This, unfortunately, is the power that these effing cell phone companies have!! And if they condescend to unbar it, do you think there will be an apology for the utter infuriation it has caused?? Not a chance! I wish there was some way the public could gang up against the cell phone companies and give them an \Up yours!"for a change!!"""