Well, Have 2 Verizon s7's in the household, both with Samsung Pay installed. Both work just find (in regard to Samsung Pay) at the local grocery store, Starbucks, Walmart.
Perhaps you are not positioning properly in regard to the point of sale device you are dealing with. You do have the Samsung app displaying the card and then you are correctly activating the communication between the S7 and the point of sale, right?