There isn't a "reversal" mechanic, but you can perform While Rising moves (some characters get 236 stance moves) from the ground in Face Up Feet Towards position or Face Down Feet Away position. Some of these moves can interrupt your approach, some can beat out your throw and some have tech crouch frames that also deny your throw.
If you must throw them, the best thing to do against players who abuse this is to walk up and then guard. They'll attack, it'll get blocked, and then you'll probably be in good range for a throw.
The best way to avoid throws is to hold G and mash A or B. When you feel throws coming, make it a habit to mash A or B while holding guard, your break percentage will go up.
Remember to only do this when you feel the throw coming but you're not sure, as standing there and mashing buttons may slow your reactions so you can't step or duck whatever big moves the opponent throws at you.