groomer wont respond to my dog shaver burn and complete loss of hair over 1/3 of his back side

Question
took my dog "jake" English Springer Spaniel, to be goomed 8 mo. ago, he came home itching and I noticed dry flacky skin and kinda OF a wavy look to his coat in a large patch around 19 X 7 inches. kIND-OF LOOK LIKE HAIR THAT MELTED & WAS FUZZY DUE TO A BAD PERM. They gave him a summer cut which we have never had done before. WHEN HE CAME HOME he behaved as If he may have been allergic to the soap, took to vet gave him anti invFlamation & anti itch spray, antibiotic's and cover his area so he won't scratch. It has been several month's and no more scratching just hardly any hair growth, groomer refuses to help say's the clipper burn was secondary to sensitive scalp infection . I just no the way I't's going I'll have to go the smaLL CLAIM'S BECAUSE iT LOOK'S TERRIBLE & SHE REFUSES TO GROOM HIM IN ALL THE OTHER AREAS. HE  LOOK'S AS THOUGH HE HAD A SURGERY OR CANCER TREATMENT'S. wHAT DO YOU THINK i SHOULD DO????? hE'S 11 YRS OLD AND HE'S MY THERAPY DOG FOR 11 HYRS.
tHANK'S FOR ANY HELP, VERY INTERESTED TO HEAR YOU VIEW POINT  

Answer
Small Claims? Good luck......
What to say here is get another groomer.
A "summer cut" for any breed that is meant to have a coat can cause all sorts of snafus and who's to say why. That there has been no re-growth is the problem and that is veterinarian situation. I would be more concerned with a vet that can't diagnose clipper burn or allergies or good ol' cocker skin that is, frankly well known, highly prone to all sorts of skin problems as they age.  That is a LARGE patch!
The shaving more than likely was the trigger that uncovered an underlying situation you would have had to deal with eventually- having had a cocker myself and spent thousands on skin care... and seen it on many of the breed, I think I speak from, albeit anecdotal, some long term experience.
So while I understand your frustration, I feel like you had the perfect storm growing and not enough people around you with experience and common sense to work with you on the problem. A dermatologist would be my first suggestion. Diet and medicated, NOT OATMEAL, shampoos that are highly diluted need to be looked into as well. I think you learned the "summer cut" idea is not a good one for your dog. Better to have it thinned out and trimmed as opposed to shaved.....
Just a thought if this is on his saddle I would look into a thyroid panel to make sure this isn't related. Often hair loss is the first indicator- especially in older dogs...
sorry I can't be more helpful.