Request for ******** authorisation of debit order

I have been writing to this forum for a number of years complaining about the same company that is hellbent on debiting my account for an account that I paid up in 2018. On the 28th of July they debited my account again despite the fact that I had not authorized the debit order. I had to go to the police station and make an affidavit, take it to the bank to prove that I don’t owe these people anymore. The debit order was reversed. Once again this morning I woke up to an authorisation request from them. I don’t know what to do with ISmart because every time they’d debit my account and I’d write to this forum, they’d write back and apologize but still continue to ***** my money.