First of all, honestly I would be terminating with a child that age acting that way! Secondly, why are YOU buying pull-ups and wipes? Shouldn't the parents be buying those and sending the child in a pull-up since she is clearly refusing to use the toilet at your house? That kind of behaviour from a 5 year old would be completely unacceptable to me and I would think it unfair to the other kids to expose them to it. You either have to have a really clear action plan to which the parents agree and start coming down hard with serious consequences for destructive behaviour etc or you ahve to terminate and cut your losses.