How Tracker treats its 'valued clients'

My previous car was protected by Tracker. I had a debit order in place for my monthly installment and everything was smooth and hassle free. In October I replaced the car with a newer model and again had Tracker fitted. I apparently even have the same account number. Despite a specific request to continue paying by debit order for some reason this was not implemented. Yesterday I received via email a letter of demand entitled '30 day notice' demanding immediate payment of my new installment which had not been paid. Despite the implicit threat in the letter I was referred to as a 'valued client'. I made immediate online payment and emailed proof with a request to be contacted today to discuss a debit order as a matter of urgency. It is now almost midnight and I am still waiting. This is stressful in the extreme to me as a letter of demand could damage my otherwise impeccable credit record and rating, and it is not my fault my explicit request for a debit order was not implemented. I want a debit order to be put in place as a matter of urgency to avoid this stress again next month. But Tracker are not interested. This is a disgusting way to treat a so-called 'valued client'. Oh, and their mobile app sucks too, it impossible to install. Not impressed.