As a travel claims handler (not Morethan!), I sometimes appoint Cunningham Lindsey to interview customers about their claims. CL aren't targetted to find fraudsters and charge us a standard fee for every case. The interview may be over the telephone or face-to-face. We often use them to clarify circumstances by taking statements or check documentation provided.
To be honest, if you call every day, making threats of complaining to
FOS and refusing to be interviewed, they will merely become even more suspicious and wonder what you have to hide. Attitiude of the customer is one of the most frequently used fraud indicators. I've had cases where
FOS have supported my decision to appoint CL because of issues with the claim, so escalating your complaint may not help.
I would suggest that the best way to resolve this is to express your dissatisfaction with the delays, willingly go ahead with the inteview, be honest about what happened (even if there are bits you can't remember) and see what their decision is.
If the claim is declined, you can of course complain. If the claim is agreed you can request
interest at 8% from the date that you submitted your claim.
The key to getting this resolved is to remain calm and let them complete their investigations. I hope you get a good result. Keep us informed.