I'm Demanding Stayforlong Fulfill Its Legal Duty to Issue My Missing Invoice

I purchased a 1-week stay at the Hilton Garden Inn Istanbul hotel through Stayforlong for the dates June 7-13. I made the total payment of $438 upfront through the app before checking into the hotel. During the reservation, it was specifically stated that since the payment was being taken through Stayforlong, the invoice would also be issued by Stayforlong.
After my stay ended, I requested an invoice through the app on June 16th. Despite sending multiple emails afterward and speaking with a customer representative, I never received any invoice. Each time, I was told that my request had been forwarded to the relevant department, but despite time passing, no concrete response was given, and the invoice still hasn't been sent.
I am requesting that my invoice for the $438 accommodation fee collected by Stayforlong be sent to my email address as an e-invoice as soon as possible, in accordance with legal requirements.