Pathetic service

The service I'm getting at telkom is very pathetic. I recently renew my contract at waterfront Bloemfontein. In the contract it state that I would receive a voucher worth R500 and I never received anything. After multiple conversations with the consultant its just not happening, I even phoned the call centre they couldn't help me. It's so frustrating cause they kept phoning me to renew my contract but now they don't reply to any of my messages.