Did you check to see if water is going into and coming out of the filter? You may have a frozen/clogged/ filter housing or filter.Try removing the filter and see if water is dispensed. It is my understanding that Samsungs, unlike many GE's, will dispense water without a filter or bypass in place (btw if you work on many GE's, do yourself a favor and keep a couple of filter bypasses on your truck. I've cursed myself many times for not having one).
If water is dispensed, then your problem is either the filter or the housing. If they haven't replace their filter in a while, try replacing filter first, if that doesn't fix it, they needed a filter anyway.
if after removing filter and water is still not dispensed, check your valve to see if water will flow to the filter. Disconnect line to filter then engage the valve. If water comes. out of valve then more than likely a filter housing problem.
Also check temp settings. Last time I had this problem with a Samsung, the fridge was set to 34 degrees... housing froze.