Vodacom : broken promise/agreement

Vodacom verbally promised me 2 months free rental as they had taken an exceptionally long time to connect my line and wanted to prevent me from going to another company. Now that the monthly debit orders are going off nicely they have reverted back to denying me the free rental. Basically the manager called Colleen **** to me. I believe we should honour our promises and Vodacom has failed dismally in their service to me. I am utterly dissapointed and would not recommend them to anyone and will never renew my contract with them. What a big mistake from my side.