Speaking from a person who works in a repair shop, you should be holding the shop accountable for the quality of the work.
If that is not an option, you can use super glue, but it's something that should be regarded as a last resort. There is a risk of brushing glue over your camera aperture, part of the LCD or some other part that is exposed just under the glass. On your S5, I'd probably just be worried about the front camera, ear speaker, or maybe the menu flex at the bottom of the device. Look at the teardown guide and see what is near the area you have to glue, and if you go ahead with this, use as little glue as possible.