No help in sight

Terrible customer service trying to get an EXPIRED hold removed on a transaction. I have engaged with four separate service consultants on WhatsApp to try to get the matter resolved but I have not been able to. I am a previous employee and I used to work in the card payments department and I can't understand why I need to get a formal letter with a letterhead and all sorts of nonsense for a transaction that should have automatically been reversed because of the payment clearing rules. I have repeatedly asked the consultant on my WhatsApp chat what email address I can use to send a letter from the merchant to so that I can just resolve the matter but even that is being ignored. Please follow up on my interactions with the bank.