PartyPeteShop - Did not receive my purchase!

Hello everyone! I do apologize if I shouldn’t have posted this here but I’ve tried all other options and I have not receive a single response.

I made a purchase on PartyPeteShop on 24 January 2020 for 19M worth of gold. I was told to meet in world 438 upstairs of the east Varrock bank. I was sent a trade offer for 19M but then the associate declined the trade offer and logged off. I did not receive my purchase. I have a screenshot of the declined offer in-game as well as screen shots of our chat conversation on their website. Not sure what else to do?