Refund coming up short

Made a booking on their system and the transaction deducted the money from my account on four different occassions. The system refunded me for the fualty transaction but the refunds came up short with nearly 10%. I have logged a complaint with three different Airbnb comunity experts and I have not been able to get any updates on when and how they will refund me. They say that they cannot find the transactions on their system even after I have provided them with the transaction reference number they sent to me. I will probably never use Airbnb again.