Bad service from vodacom and forever charging pricing

Hello Peteri have a problem with vodacom since when I bought a contract phone for my son.The contract was for R550 a month for two phone,mine is old one I pay R199 and my son's is R350(total amount R550)Now they charge close to R1000 for this phone and I have been trying to reach them to cancel,they say they are able to cancel only for one number which is mine and the other number they can't because the is a cancelation penalty of R2500 to take it back to the original package of R350.please help,I'm so frustrated with vodacom and their bad serviceNB: I'm their loyal customer +/- 30 years.whats happening with vodacom this days