No Call Records when things get sticky???

I am very disappointed with the service that i am receiving. I've spoken to so many call centre agents. My husband called to check if he qualifies for optical visit and lenses and it was confirmed that he qualifies even though he went last year which was why he phoned to confirm first. He did not know it was only every 2 years. His frame broke which was why he called and he was told yes. He went for eye test and new glasses but claim was rejected and now we are responsible for the bill and my husband urgently needs his glasses. Now we are being told we never phoned according to your records and call log. First 2 agents checked your logs without even asking from which number he called, so how did they even check, how can they confirm no call logs without knowing the number dialled from? 3rd agent at least asked when i mentioned this but said no records found. We have a call log on our phone proving the time/date and length of the call and Vodacom will be able to verify this. To me this seems to be quite convenient to say you cant find it after rejecting the claim. I would appreciate a call back and explanation from management.