A telkom wifi rooter contract that was supposed to be cancelled

I spoke to Khanyile from Mondo on the 4th of July who assisted me with cancellation of my wifi contract telephonically. She advised that my contract was cancelled as I've lost it. Today I got an invoice from Mondo saying that I need to pay for the lost rooter's contract. When I called Mondo I spoke to Perseverance at 14:34 today and she advised me that when a device is lost Mondo doesn't cancel the contract. I really do not understand the relationship that Mondo and Telkom have because now Telkom is telling me that if I want to cancel I will need to pay for the penalty fee. I am not going to pay for any fee as I was told that my contract was cancelled and I cancelled it 7 days prio. The reason why I had to request for another device was because I thought my other contract was cancelled. Now I have to pay for double devices which is unfair. I regret having a contract with Mondo.