Trying to rob me off a R1000

I have been a vodacom customer for 14years and have not experienced one problem. Today I call in to find out what my debit order amount is and im informed it will be R1945.00, This is wrong as i upgraded my account and have also cancelled another line. The agent Katlego tells me that im paying for the airtime i used in July. How can july's debit order go off end July, then why When i took out the contract i was debited twice in one month. one amount pro rata and end off month R145 and received R135 airtime per month. Thus it means When then debit order goes off end of that month im paying for the airtime or data im will recieve in the new month. Now these ****** wanna rob me. I will take you to court please fix your systems.