02 Fabia 1.4 16v heater with a/c stuck on hot

hi all,

the gf's 02 Fabia 1.4 16v heater with a/c is stuck on hot, no matter what i do it just stays on full temp.

did a search and came up with a poss flap motor fault but there wasnt enough info.

can anyone point me in the right direction with this as its driving her nuts.

the car used to get cool if the ac was used but tha no longer works either - could need a regas though.

if there is a part needed where would i get it?

ta

Dan