Backhand problem

Hello Coach, 

I'm just-ahead-of-a-beginner level but does not use the same bat every time. Irrespective of rotating bats every time, I was gaining a good backhand (both in chops & smashes), but of late something happened as I played using a different bat. Every time I try to play a backhand smash with a good level of confidence, the ball tops out of the table and even chops started falling short. Eventually, I lost whatever backhand power that I gained before. My backhand shots used to be spot on and aggressive compared to my forehand.. Forehand topspin is good, chops are good and learning to loop. Forehand is not that aggressive when compared to my backhand. 

Should I upgrade and stick to one single bat? If so, what would be your "blade and rubbers" suggestion for me? I am based out in India and as I said I'm ahead of beginner level and things mentioned about my game style, I'm looking for an intermediate bat to improve the quality of my game.

Pls suggest.

Thanks,

Dev