“Following an accident that was not fault

“Following an accident that was not fault. The 3rd party admitted liability at the scene. Phoned AA and initially they told me because I lived in wales I needed to find my own repairer and they required quotes to see. Eventually after much back and forth they agreed to take it to a garage they use. The garage did not fit the car correctly and following been told it’s just water marks and independent assessor has stated there is over £560 plus VAT repairs still to be complete. The AA offered me £78 yo take it to my own garage and get it fixed. They are now refusing to provide me with a courtesy car that fits my family (3 car seats in back needs) if the car goes back to their repairer to fix the work that was not done initially Avoid the AA. They don’t look after customers. When trying to claim for car seats their response was “that is just life” They also refuse to give a like for like car as a courtesy car even though they had admitted full liability that the repair work was not to standard.