Overcharged

I previously reported DSTV for overcharging me for several months on price lock , they responded but there response was that they have credited my account for May . My question to them is what about all the other months that i was over charged ?but i received no reply , I do not recommend DSTV or PRICE LOCK as they overcharge you and its impossible to receive the credits owed . I HAVE BEEN OVERCHARGED SINCE SIGNING MY PRICE LOCK CONTRACT , calling the call center is a waste of time . Do not sign a contract with them