Costing me money

Firstly I got a phone on contract from Vodacom. Since June when i got the phone it already went in for a repair after struggling with it for 2 months. Now I am on standby ,my phone goes directly to voicemail and the phone is on and on load speaker, happened 5 times in 2 days time... Pay money for service which i don't get, loosing money of not receiving call outs! Service from personnel at Hi Cell in Standerton is absolutely pathetic. Not helping with problems in a professional manner