how can i fix a mira go shower holder?

the shower head keeps falling down the pole it just wont stay up in the air and this is making life difficult to shower as i have a bad arm and cannot hold it up all the time. the shower pole was only fitted from new less than 1 year ago, is it just a simple matter of tightening something up in the holder part.it is the white plastic part that holds the shoer head that just slides down the pole and sits on the soap dish