Hills science dog food & Bromhof Veterinary practice randburg

I bought Hills science metabolic range for my dogs that I buy every two weeks as it was recommended by BromHof veterinary clinic, after diagnosising my mini pin with diabetes ( insulin x 2 a day) They had put the same size bag in the place I've always picked up from, and I paid, only to realise after taking it home and opening the bag it was for large dogs, I ubered back told the receptionist, she said chills science dog food offers 100% money back guarantee if dogs wont eat the biscuit so I can bring it back, I did not want the money just the correct pellet size and correct food. As I was leaving a young female vet, asked me where are you going with the bag of food, I explained what had happened and she said no it doesnt work that way . As the practice ( Bromhof veterinary practice.randburg) will loose out, I had to leave and she said she would contact hills and call me. She said I must collect the mistaken bag back and I am liable for the bag I exchanged it for. As I made the mistake and there's no money back guarentee from Hills science dog food for me. As we all know vets are costly and so is Hills dog food, I was disappointed with the veterinary practice treatment towards me after they know I only buy Hills from them as the metabolic range cannot be bought in pet shops Hills offers false advertising as there is no money back guarentee or the vet was just making my life difficult. I mentioned is it not the vets job to ask when someone is purchasing a special diet food to ask what type of dog do you have, instead of letting a person pick up the totally incorrect bagel even though it was a metabolic range the vet rep****, no it's not our job you should know , we cant remember every dog that comes in Very rude and I cant believe Hills Science allows a practic to sell their products with this attitude