update: he gained a lot of weight at the breeder, and was relaxed and happy when i took him home 2 days ago. he was active and eating well (mainly cooked chicken) and his stool was solid.

on the next day he started to have diarrhoea. he was sleeping all morning and did not touch his food/water. later he woke up, was playing but not eating well. i recognized that he is licking the wall, glass windows and sometimes the floor. i've cleaned everything with water to remove any disinfectant or cleaner what i have used previously. he still lick the wall and have diarrhoea.

i have contacted the breeder again and she advised to feed him with raw chicken instead of cooked chicken, because that is what he was eating all last week when he was with her and it has more minerals, etc. i have mixed it with cooked chicken to see if he will eat it. no success yet.

i'm very close to give it up and take him back to the breeder. she offered to give the money back however i'd like to have a cat. i'm just to affraid to go through on the same when the kitten was with me first time.

Some cats don't deal well with abrupt changes in diet. Maybe that's what's upsetting his digestive system. Raw and cooked are very different. Can you maybe get a half-week supply of the food he's used to? Do you know what recipe your breeder is using and can you replicate that? He might need to be transitioned more slowly to a new diet.