@Miriam Thnx for the encouraging words!
The tension was WAY off and the number plate could turn without me turning the tension so that was loose. I took the tension parts off cleaned it. The tension stud was bended, i had to carefullly bend it back and put the whole thing back together at first the tension was still way off and even if i put it at 9 it was still not tight enough. I had to tighten the threaded nut a bit and than put the numbered dail on so it was all a bit tighter.
I think i had the same problem as Plume with the tension. O and i did have problems with the cheaper tread at first but now it takes all tread.