Stellantis Financial Services review: 110 days and still waiting for a refund!

Are Stellantis in financial trouble? After fully paying in full the termination agreement with the figure they supplied 12 days later they took a payment £364.75, 110 days ago then 2 days ago they took another payment this time over £1400 from my account. They have said they made a mistake (mistake 1-Failure to close the account, Mistake 2- grabbing a payment, mistake 3- failure to return the money, mistake 4- grabbing more money!) after being one hold for ages (all managers were in a meeting!) perhaps they were in a meeting to see how many more over payments they could take? Apparently they can't do anything to help for over 12 days! So I am sitting here financing Stellantis financial because they don't care and have no interest or concept of customer service.