Complaint

We have,unsuccessfully, been trying to communicate with MTN. We gave up in September 2019 and terminated the contract as it was time for renewal. We double checked all was paid up to date. Suddenly in March 2020 we have people, on behalf of MTN, threatening us for money. We, again, attempt many times to date, to speak/email to MTN and, still to dtae, have not had the courtesy of a reply. Could you assist please??