Vodacom ******** people

I got a contract phone fir my mother and recently she experienced a problem with caller Id. Whenever she receives a call it comes up as unknown caller. I phoned Vodacom and they said they can fix the error (which is not related to an error with the phone but with their services) and I was told they will fix it at a cost of R9.99 every month. This is not stipulated in the cobtract we signed and is an error on their side as it worked fine for the first year that she had the phone. I was told that the caller ID services expire after time. Never in my 17 years of using cell phones has this ever been been mentioned. This is the last I will ever use Vodacom again. Next cobtract will go over to MTN as they never charged me for caller ID before.