Check for wear irregularities. Rebalancing a tire with irregular wear can cause it to vibrate.
If there are no wear irregularities, have the wheels spun on a machine that does “road force balancing”. That provides a much better balance than a regular machine, and it will detect irregularities including a bent rim.
Check to see if your tires are directionally oriented and if so that they’re installed in the correct side. Directional orientation can be found by looking up your tire on the internet, by the existence of an arrow on the sidewall, or a quick visual by anyone familiar with tires.
If they simply tell you you have a bent rim, make them show you. I have bent a rim (two actually) but I have very often seen a shop simply blame a vibration on a bent rim when it was actually a sloppy balance job. Too many bead busters simply don’t want to bother doing a good job balancing.
Question: how many miles do the tires have on them?