Recently I bought a cat from a girl not too far away and she got the cat used to drinking milk. The first couple of days we gave it milk while we asked the pet shop people what would be the best food to give it. Two days later we start giving the cat solid food and it doesn't want it. We tried canned cat food mixed with it, cat milk mixed it, and the foods alone and the cat wants nothing to do with them, except for the cat milk. It will drink that.
Now my cat is sick all the time, it has ups and downs and it still doesn't want to eat. We even tried different types of dry food to see if it was picky, but no luck. It’s been a week and a half now and it keeps on not eating. What should I do?
Milk, even if it is "cat milk," is not a balanced diet for cats and you are right to want your cat to eat a well-balanced cat food diet. Your cat does not have to eat dry cat food; in fact, there are recent studies that suggest that an all canned food diet may be best for cats. For much more information about feeding cats, please consult the diet sections of this website.
Keep in mind that finicky cats are created by overly-accommodating owners. By starting your cat out on only the milk sold by the pet store, there is a chance that you were giving in too soon when you tried to feed the cat food. Of course, your kitty preferred the milk, so she held out for that. And, every time you gave in, you likely showed her that she would get what she wants if she just held out long enough.
At any rate, going this long without eating has probably made your cat sick even if she wasn't ill to begin with. No matter how you look at it, a cat not eating for a week and a half is not normal, is quite dangerous, and probably indicates that there is something else going on with your cat medically.
The only thing I can advise at this point is to please bring your cat to a veterinarian as soon as possible.