JPMorgan Chase Bank Account Or Service Complaint

JPMorgan Chase Bank account or service department,

Other bank product/service Account opening, closing, or management California

I sold a home and the buyers financing bank did not close escrow on the date anticipated. Escrow was 60 days and I have the buyers pre-approval letter, for my property, from the bank dated 64 days before anticipated closing. This cost me approximately 15 days of extra interest I had to pay on my mortgage loan. This cost me $850.00. I have contacted the bank as well as my real estate agent. There official '' response was per real estate agent, they are declining reimbursement request, their reason is because I am not their customer and thus not a party to their transaction. They offer absolutely no responsibility for delays they caused and will not directly respond to me in writing other than the phone call that my real estate agent received with this information. I would like to pursue reimbursement of 15 days of interest. Thank you for any help. I am also not really sure what category to place this in.