Refusing to cancel my contract

am extremely disappointed with Mondo Cellular’s handling of my account. In December, I was offered a contract, but the mandate expired and there was confusion around the device. I believed no contract was in place and purchased my own phone. Despite this, a debit order was processed on 20 January without my authorisation. I immediately contacted Mondo to cancel the contract and request a refund. Despite my cancellation request, they delivered the device afterward. I have not opened or used the device. Mondo is now refusing to cancel the contract, claiming I accepted the deal, without providing proof of a signed mandate or call recording. I find this treatment unacceptable. I request Mondo Cellular to immediately cancel the contract, collect the device, and refund the amount debited. I am posting this publicly to warn other customers and to urge Mondo to resolve this matter fairly.