If your having that many problems ask them to use a tension meter on the spokes, different size spoke require different tension but each sides spokes should be relatively close to the same tension. To be fair the chain side usually requires more tension than the other. I have had to retension factory built wheels before but usually if I'm going that far I'll relieve all tension, lube the nipples and true and tension from scratch, so not very often.

If they don't have a tension meter, find a different shop.