Unresolved Accounts complaints since May 2015

Since Vodacom increased their pricing in April 2015, I have been receiving additional subscription charges on my data contract every time I use one of the multi-sim cards. The first month, two-thirds of the items I requested to be reversed have been reversed, but since then, every time I complain, someone calls me, promises me a credit but no credits are ever reflected on my account.<br> <br> I have explained time and again the history behind the account, but nobody seems to be able to resolve the fact that I am continually receiving these charges. I would like to upgrade the contract to something current, but I refuse to do that until the unwarranted charges have been credited.