Que Collect constantly chase you for money that has been settled

Que Collect are an unregistered business and claim to be debt collectors on behalf of Mobile Music Academy. However they do not follow any processes that a legitimate collections agency has to follow. They are unlisted and also operate under the names of: Que Debt and Que Consolidated. Their tactics are limited to constantly sending SMS messages to make demands even when the account with Mobile Music Academy has been paid months before. They send 2 x SMS messages a day and then phone you constantly from a spam number to insist that you pay money that has already been paid! How many other people have they tried these tactics with who would not check and would simply pay? This is definitely not legitimate and I would definitely stay away from Mobile Music Academy as a result!