Hey! Ok so the best way to deal with this is to angle the bat against the spin, so for example with a normal pendulum sidespin serve the spin will take the ball back towards the backhand side for right handers, so you’ll need to aim the return and angle to bat across into the forehand half. Of course for sidespin in the other direction you’ll need to angle the bat the opposite direction.
Another good solution to dealing with sidespin serves is learning how to backhand flick well, with this shot you can add your own topspin and neutralise the sidespin on the serve and it’s still a nice positive shot as well.
Have a look at this video we have which should help you as well 🙂