Breach of contract

Hi, I traved to Zim on Feb 18 and 19. When we landed back in ZA and i tried switching my phone on it came up with \ not registered on network\". After switching on and off and doing manual network selection finally got onto to the network only to then finad all incoming and out going calls are barred. I have 24 month contract with them but no service. Went to Vodacom Greenstone who called midrand, they said it would be fixed by Saturday evening, no change. On Monday sent email of complaint and had a reply that it was the sms roaming that needed to be deactivated and it would be operational in 1 to 6 hours, that was 08h00, 21h50 and still no calls possible.....so frustrated and dissapointed with this company and their poor service! "