Just say to Thos Cook that unless you hear from them within a week you will be writing to "Watchdog" and go ahead anyway and ring or write to Watchdog, they have a way of making things happen. You shouldn't be put through this at this time. You have our sympathy as well. Ida.
I suggest a solicitors letter with added costs. Usually speeds things uo.
Join Which the consumer magazine.(on line) and for £25 for 6 months you have access to solicitors for as long as necessary to sort out your problem. Cheap at half the price and possibly quicker than watchdog as they tend to collect a number of similar issues before using them in the program.