Terrible contract management

I have struggled to upgrade my contract since January, eventually in May a consultant phoned me to do the upgrade and this resulted in me receiving my device, only to be charged for two contracts at the end of the month..on the same number! Turns out they added an additional contract and never cancelled the old which was upgraded. I was now forced to pay the enormous bill to avoid service suspension all the while I am still waiting for feedback. Service is ridiculous!