Discovery Health - I won't pay!

Discovery Health (and Insure and Vitality but those are complaints for another day) have quite clearly not prioritised having proper controls and processes in place to ensure their customers receive the best possible experience as a Discovery member. I am appalled by the blatant lack of accountability I had to witness recently. In June 2018, we made to decision to send our daughter for a dental procedure because we had enough funds to cover the cost in our savings account. Due to a mistake Discovery made, the claim was paid from the hospital benefit and by the time they discovered their mistake at the end of 2018, my savings was depleted. Discovery tried to reverse the claim from the hospital benefit and recover it from savings 6 months later and surprise - no funds available. They now have the audacity to hold me accountable for the cost and are insisting I refund them the amount. The way it was communicated to me was also utterly unacceptable. I want to understand why I need to be held accountable for Discovery not putting the necessary process in place to prevent this error from occurring in the first place. I will not pay this claim because YOU made the mistake and it took YOU 6 months to figure it out. The reason for going ahead with the procedure in the first place was solely based on the fact that the funds were available and now I have to pay out of my own pocket.