Not cleaning properly

Its been 4 months since i bought the robovac
It was working perfectly fine but now suddenly it makes some kinda buzzing sound while cleaning and also the vacuum setting even on strong is not working properly as before ( not increasing suction power )

Hi, you may need to clean/replace the filter of the dust box as it may be choked up with dust. The crackling noise may be due to wrapper/some paper stuck in the main brush. A basic cleaning and maintenance of the robot will solve all your conderns.