It took me a year to get Suki to eat right, i did all the wrongs things, hand fed her, gave her nice treats, added to her meals and all it resulted in was a fussy little moo who wouldnt eat and was underweight.
BUT then I got tough, I was strict with the meals, the times and not leaving food down, I banned all treats and titbits and did not veer from this,
she didn't eat a thing for a week - I was tearing my hair out even crying!!! whilst she was just prancing around waiting for hand outs!!!
but after 2 weeks she gave in and ever since she eats 2 good sized meals of just dog food(kibble) and nothing else.
I will occassionally add to her food as a treat but if she turns her nose up at the next meal which she does at times - i take it straight up and she gets nothing till the next meal is due even if thats not till the following morning!!!
Its hard work especially when your convinced that they will starve to death but its worth it and it will iron out in the end if you stick to your guns
and as Karlin said if your really struggling speak to the rescue for you