Vodacom most useless customer service

Worst customer service I ever received from a mobile network company, went to the phoenix plaza shop to cancel my contract over a year ago, but was told they don't do that at the shop and must call the call centre department, which I did immediately but no invoice was forwarded to me to pay off the phone, so I waited a couple months to see if their is any response cause I a very patient person, but to no avail, so eventually may this year was supposed to be when my contract should of been expired but wasnt , and to top things of, the last year of my payment my premiums went from 299 a month to 320, and when I questioned the staff at the plaza branch all the lady says is that the option I was on changed, my question is, how can you sign a contract for one amount n during the contract the amounts change without notification. From my previous contracts with other mobile networks once your contract expires it automatically goes to prepaid or stays on contract but the premiums drop, not with vodacom. I called the cancellation department beginning of July to have them cancell my contract cause my contract should of been expired n premiums should of been cheaper after may , only to be told i will be charged again in July and the premiums that went of was even more, r358. All in all I will never shop at vodacom again has the call centers are even more useless