adam,m,bb plz read this asap?

hi adam,m,bb its dy2 again didnt think i would need tov ask any more questions about my bike again but here i am i got my bike back today after it being mended but it isnt it went in to be done because it was trying to start but wouldnt and when it did it wouldnt go over 20 mph. well i got it back and it was ok ive come to use it tonight and it wont go over 10 mph again and now it wont start again everything was checked no blockages anywhere carbs had good clean its fine then i go to go out on it and it packs up on me ive tryed everything to get it fixed dont know what else to do .i havnt got any more money to spend on it ive spent over 250 on it to try and get it right but all spent out now as i,m only 17 and at college plz help thakyou .