HELP ! my cistern wont fill up !!?

Someone please help !!!
recently i have had to purchase a bottom entry torbeck valve due to the old one not being able to cut the water supply off once the cistern was full, so instead of replacing the whole valve i changed the blue plastic nut back to the float, leaving the old pipe, this seemed to go pretty well, untill now my cistern wont fill up, the water flows out of the valve but it is now flowing straight into the toilet (i think), if i lift the float t cuts of the supply but the water just disappears, to make matters worse the cistern is inside of a vanity unit (push button flush) so cant see inside of the cistern due to the unit top. Any ideas ???????