Help! - Maytag bottom freezer refrigerator won't cool the fridge part -?

Hi - I have a Maytag PBF2253HEW bottom that's about 7 years old. About three months ago the top refrigerator started to not get cool while the bottom freezer was working with no problem. We had the repair guy come out and replace the Control Board and another small part that he said cost about $15 but it was not worth not replacing that as well. Paid $250 for the repair and it worked for a couple months and then the same thing happened. Called another repair person and he replaced the thermostat (clips on to the copper tube) and what i believe to a temp sensor which is about 1 inch long, white plastic and the thickness of a thin pencil. He was adamant about replacing the control board but I declined as we had just had that done. needless to say, he did not provide a guarantee as we did not accept to control board to be replaced. Of course, four days later we now have the same problem. Could it really be the control board that was just replaced went out again after only 2 months or are there other factors at play?

We really like the fridge and don't want to spend $1,000 to replace it, but at the same time we've already put in $350, some spoiled food and the cost of this to come repair bill. I'm thinking of doing whatever you recommend myself so I know what is happening to this fridge.

I'd appreciate any feedback you could provide. Thanks!