Dublicate Cell Phone number between Cell C/Telkom

Dear Sir, We contracted a R99 per month plan with Telkom Mobile via INTERNET and the phone was delivered by courier only with a delivery note this month. NO contract papers. On activating the phone on the 21st February we found that we could receive no calls to our number. In order to check we dialled the number allocated to us on another phone, then also on our new Telkom phone simcard. Both times the call was answered by a gentleman with the name of Justin who claimed he had a pay-as-you-go with Cell C with the same number I was allocated with. He had Ported the number himself on the 30/6/2014. I asked him what number I had called him on and he said it shows incoming call from his own number! I asked how is this possible? I have been to the Telkom Mobile shop every day for the past week without them being able to resolve the issue. I then went to Cell C store at Bridge Mall and they were most helpful but the Porting official said that Telkom Mobile Porting must communicate with Cell C Porting Dept to resolve the issue! At this stage we are no further than two people having the same phone number, ourselves with Telkom Mobile and the other party with CellC. Please help