*****ulent activity happening in my account

I'm writing this as a angry customer due to the ***** that has happen in with my phone contract Vodacom has bridged my contract with me signing any thing the agreement was for me to pay 420 now I'm paying more than what I agreed on when I check in the invoice a handset was added who agreed on that I don't know kindly do the right thing or dis matter will escalate. Account number is I***_9 cell phone is ***