My sonicare toothbrush loses power

Hey my sonicare toothbrush sometimes works, sometimes doesn't turn on any lights. If I hit sink couple of times with side of bottom it will turn on (lights up) and will work but then again does not.

Rubber button is in perfect condition. Clicky as always and works 100% time if lights are on.

It's exactly 3 years old.

Also it seems it's more difficult to take it off the charger but if it's in "working mode" it will charge normally, maybe something about the magnet.

What can I do?