Can I tell my landlord's worker to fuck off?
Why do you want to tell them to fuck off?
They have been bugging me for a while now.
It can be upsetting to have somebody bug you all the time but you cannot tell somebody to fuck off. It is rude and it could get you in trouble if they are only doing their job.
Whatever, they can't kick me out cause they are not the owner.
Instead of berating them, ask them nicely to stop what they are doing. You could also take the issue up with your landlord and file a complaint with them instead.