No refound for trips in holiday package

claudianamr

I buy a holiday package from Thomas Cook in October 2019, it was 568 pounds.After they collapsed I have received 500 pounds back but the rest of 69 pounds what it was payd for 2 trips they tell me that they can’t pay back.Thomas Cook colaborates with Olympic Holiday and they tell me that they can’t refound because the trips was booked with other agency. I asked them the name of that agency and they tell me that they don’t know. I asked my bank to help me, they tell me that Olympic Holiday must know surly . I send them another email and I tell them what the bank tell me, thet they know, and they do not respond. What can I do?