When we had the same problem (that we were unable to bag chips), we usually made a count with a floorman or at least another dealer.
After finished counting, and all player signed their chipstack, me and other floormen started counting them again and made the sum to see if it was ok with the total amount of chips. If we found a mistake in a count, we used to call the player at his phone, telling him that the count was wrong and, since we had a camera on top of every table, we could provide the player with a camera check.