Hello,first my shower head was leaking abit of dripping then more and more water, now my geyser won't work , what shall I do ? I rent the flat not own it and the owner is abroad

Dripping from shower had has nothing to do with the shower head. Dripping is an indication that you need to replace washers ( or cartridge) located inside your shower faucet. To do that, you will need to turn off water for the whole house, remove the stems ( or cartridge ) and replace washers ( or the entire cartridge ). If you have never done that before I would suggest you call a handyman or plumber. As far as the geyser goes, I don't know what "geyser" is. Can you be more specific ? Back to you. Milo

Geyser is the appliance you use to heat water on the bath

Either the diverted needs to be replaced or you got a restriction in the line that comes out for the tub spout