Shaping Leggings

I have three pair of these that I bought 4-5 years ago. They were S/M and fit like a glove. Being as old as they are now and having been worn A LOT, it’s time for new ones; however, something is amiss in the sizing. Somehow since I last shopped for these, the S/M became more of a XXS/XS. I compared them to my old Slimmes and there is at least a 2” difference in the waist. I exchanged them for the next larger size and they were HUGE. I’m very disappointed and wish that the manufacturer would add back the S/M at the old measurements and resize what it currently offers as XXS/XS.