bad service from Momentum after so many years of being a customer

I have been a client of Momentum insurance for a long time, sure over 10 years. I changed my policy about 2 months ago. I was not informed that there was a shortfall on the debit going off at the end of March. Then in April they took the new installment with the arrears amount. Due to no confirmation that my account was apparently in arrears i returned the additional debit order that went off my account. Never in all the time i have had a policy with them i had an unpaid debit order, but because once i was not sure of the extra debit order i am being penalized on my monthly discount. I paid the money the next day via EFT. I cant believe this is how they treat their loyal customers. I am in the process of looking for another insurance company.