Not able to fix my phone

My phone has not been working since the 1st off April. My internet, and I can't receive or send messages or calls.I went to Vodacom 4u in the mall and they were able to fix my phone. They said my call limit has been overlapped from March to April. My phone worked for about a day and I went back to them and they just changed my limit from 50 to 70 and on the 7th I made a call for about 3mins and they cut me off again saying my call limit has been reached but when i checked there was 75mins left. I went to vodacom for the 3rd time but they were not able to help me because head office put them on hold. I am getting tired of going back and they are not able to help me. I have been paying R500 for month! I don't understand how it can be my fault. I've been paying every month, and it only has problems now.