Disgusting service!

i upgraded my contract in the beginning of July , they proceeded to bring me a wrong device. i had ordered a p40 lite and they brought me a smart 2021, called them back to let them know....they fetched the smart and to this day I'm waiting for the p40 lite, i have called over 20 times to query why i have not yet received my device only to be told today that my account iOS under investigation because the courier did not deliver the smart to them. after all this time! this is disgusting service, where i asked to cancel the contract i was told i cannot. how do i open a case against Telkom?