Refusing to refund cancelled Comair (British airways flight)

I purchased a return flight ticket on the Computicket website in May and the flight was meant to be in September, for a British Airways flight which was operating under Comair.

Comair is now liquidated and Computicket id refusing to refund my money back they are telling mt to contact British Airways and when I contact British Airways they are telling me to contact Computicket because i purchased the ticket via Computicket