VODACOM very bad to use.

Have never been happy with Vodacom and is going to cancel everything with Vodacom. I have upgraded one of my numbers. Paid as usual my account at the end of the month. Now suddenly I am in arrears, but the account has been paid. Not one single month that I can recall is my amount the same on my account. One month back I cancelled Vodafone live which was R320 extra a month and eversince my account differs each and every month. If you are given a credit for things put on your account it is suppose to be less, but my account stayed the same amount. How on earth is that possible. Just not happy to phone each and every month with a complaint. My account is over the R3300 each month and I am fedup with this account now.