challenges

playing the challenge for bingo games  have played more than the 15 required  twice a t least  but do not get credit for it as it is locked on 6  how can this be cleared  up.   So many times featured challenges take a lot more than they return.  I do not like the featured games offering extra free spins as they either do not happen or do not begin to pay a fraction of what has been wagered.  Have tried up to 500K and received nothing after losing several million.  Lots of ties after 250 spins did not get a free game once.