Disappointed at Marquis

So disappointed at this company, on 8 November 2024 I sent them an email to update my banking details, no one responded except for automated email, then on 14 November 2024 I called them, they then sent me an email confirming that they have updated the banking details, to my surprise the installment has not been debited, today is 3rd December. Yesterday (2 December 2024) I called to check why they never debited, was told that they do not debit during weekends, so I tried calling again today, from 09h00 until now almost 5pm, no one picks up the calls, 6 times I tried calling them, holding for atleast 10 minutes, to no avail. I hope my account doesn't go on arrears over this for something that is clearly their fault.