92 ranger a/c probs

I have 92 Ranger with some air conditioning problems. about a month or two ago I had the air conditioning worked & had the compressor, drier & orifice tube replaced, system flushed, vacumned & refilled. Paid over $600 to have the work done. About a week or so ago it started acting up to where sometime the compressor wouldn't come on until about 15 minutes after turning on the air. Once it came on it would blow cold though. Than it got to the point it wouldn't come on at all. Took it to the shop & was told the valve that hooks to the hiside line & goes to the back of the compressor blew & it leaked almost all its freon out. They replaced the entire line. The compressor still comes on at times & won't come on at times. The shop said they think it may be the relay is bad now & isn't sure where the relay's at & now wants to send it to another shop to look it over, find the problem & repair it. Someone please tell me if they think the relay is the problem or not. I don't have the money to pay another who knows how much fixing the air, but at the same time after spending close to $800 now on the air, I expect to have working air. Someone please tell me what they think the problem is, because I don't know how much more I can take of the shop saying this is the problem, replacing it & still having no better than before. I have to have working air & after paying close to $800 I thought I'd have it buy now, but if I can't get it fixed, I'll have no choice but to trade the truck in, but after having put $5000 in the truck in 1 year I don't want to get rid of it.

Could be the relay,maybe under/over charged, a/c pressure/cycle switch. If you really want to keep it buy a manual and read up on the do s and don't s of working on your a/c system and try and figure it out yourself, or take it to a good a/c shop, because if the one you've been taking it to doesn't know where the compressor relay is at that tells me that they're either lying to you and just want to get rid of you, or they don't know what they're doing.

Thanks for the reply. I'll probably just have to buy the manual & try to find the solution myself. I personally think its the shop just don't know what they're doing. I would take it to different shop, however 2 things keep me from doing that, hardly any shop in the area are good, almost all the shops in the area are nothing but liars that will lie in every possible way in order to make more money and second I don't have the money to take it to another shop, the only reason why I've been taking it to the same shop is because I've been a patron of them for the past 5 years & do to that have an account with them to where I can pay them payments which is something I can't do at any other shop.