Paying for a phone I can't use

My phone account freezes (can't phone out or use data) on average once every 24 hrs, for the last 12 days. I've had to phone Vodacom exactly 15 times so far and the issue is still not resolved - they keep on telling me there is "a pending service request to back-office", which is a nice way of saying we haven't help you and we certainly are not going to help you right now. It takes me on average 20 minutes a call, so I've spent more than 5hrs on the phone (as they also phoned me a couple of times). I'm on a Smart L contract which I have always paid diligently over multiple years now, so I'm paying for a service I'm not getting - this is *****ing. I'm a self employed professional engineer, so the 5hrs lost is costing me real money, not to speak of the time lost where I couldn't use my phone, or now having to type this while having to drive to find wifi. This is ridiculous. I can't think of what steps to take next except moving to another service provider. Vodacom, any suggestions?