WHAT'S WRONG WITH MY MIRA 8.5kw SPRINT SHOWER?

MY MIRA 8.5kw SPRINT SHOWER HAS STOPPED WORKING WITH NO WATER COMING OUT WHEN SWITCHED ON. RECENTLY I HAD NOTICED THAT THE WATER WOULD SLOW THEN STOP SUDDENLY, THEN PICK UP AGAIN, THIS LASTED FOR 2-3 DAYS THEN THE WATER STOPPED ALTOGETHER. IT WAS WORKING PERFECTLY BEFORE THEN AND IS ONLY 2 YEARS OLD. COULD IT BE THE PUMP?