Disconnect repaid number without any notification or communication - bad service

Contract was paid up in Decmber 2024 and the number moved to prepaid. Without notice or communication, MTN decided to disconnect the line and assign the number to another customer, although the number was regularly recharged with data and airtime. This is extremely unprofessional as this number is linked to banking services for authentication as well as some other. The customer service is a big Zero on customer service and advises that it is what it is. This is utter nonsense. What happens to all the money spent on recharging the account? Number in question is ***