BA failing to credit my parents Tier points and Avios from IB

[The Original Nick]

Hi All, My Mum has just about had enough and so have I. My parents flew to Costa Rica on Christmas Day to meet me and my partner there. They flew in Business on a cash ticket with IB. I don’t know how many times I have spoken to BA about their accounts not being credited. They just keep saying we will send it to the back office. My Mum has been told the same after about 10 phone calls.
Their flights with BA LHR – MAD still haven’t even been credited from Christmas eve.

What is the next step?

BA are really annoying me now.

Thanks Nick.