Topic: Who is our contract with?

Not a cruise topic but we are cruisers and this could occur again. Booked Florida holiday with Thomson, paid for premium seating, original plane defective so Thomson Fly supplied another without premium accomodation.
We were given a letter from Thomsom customer services before our late take-off which stated that we would be refunded that element of the cost.
All fine so far, i didn't want to chance a defective aircraft and a promise of refund was acceptable.
That was on Aug 29th. Still waiting!!! 3 visits and tense metings with shop staff have yet to work.
Any suggestions? is our contract with Thomson or Thomson fly. Can we can only go through the shop to complain. so far three promises have been made and three broken. On our fourth promise now

Find out the name and address of the Thomson CEO.

Set out the facts and promises to him or her. Mention you have lost patience with them and that the TA is not delivering the promise.

Be factual. Give them telephone and e mail addresses for a fast response.

You should get a positive response.