Still waiting for a refund... no feedback from the company

Extremely bad experience with this site. We booked an hotel for a customer using our company card in September 2019, once we validated the payment we got an error message explaining that due to a technical error the payment was rejected. We then tried 3 more times unsuccessfully. We tried with a different bank card (from an other of our businesses then our personnal card) and it didn't work still. I had to personnaly go to the hotel and book with the hotel without using booking.com. The hotel confirmed nothing came through with booking.com. In the meantime we received on our cellphone several messages from our bank explaining that the transactions went through (the 4 of them), we contacted the bank to explain what happened and the bank confirmed that Booking.com can sometimes give issues and be recognised as a ********** transaction so the transaction is rejected. We immediately sent a mail to *** explaining the issue and received a pre-typed email asking us for our booking number (that we never received), our PIN number (didn't receive either) and other information. Being reasssured by the bank that the transaction would not go through we decided to leave it as is. It is only in december that while consulting our bank statement we realised an amount of 14.6k taken from our account with nothing showing Booking.com site. After investigation we connected the september experience with this transaction and immediately contacted (by email as no phone number is available) Booking.com with several screenshoot of the transaction, we immeditely received the same pre-typed email. After a few other attempts we finally got someone to answer us asking for some specific document that we immediately sent, few seconds after we received.... the same pre-typed email and no more news. We sent a new email threatening to go the legal route and received from someone else a new email asking for different document, once again we sent the required document in a nice and structured email, referencing each document by its document number, leaving no room to error or misinterpretation. What happened next? Again the same pre-typed email. Now back from the Chrismass holidays we send again all the document in a new email with a new threat of going legal and exposing this bad business practice on social media. The mail has been sent a few minutes ago aand we just received again their automated response. The bad experience seems to only start with booking.com we will go the hard way but there is no way we just give up on the 14.6k *******y taken away by this company. Seems that as soon as a small issue happen there is absolutely no assistance.