Non payment form momentum health

I am greatly disappointed in momentum health after a procedure that I had pre approval for was in the end largely paid for by my savings. I do not understand how pre-approval was given and then this is the way a claim gets delt with, I phoned multiple times and already have 6 reference numbers with no logic explanation why my savings got mostly cleared out by this claim(money I need for dental work as that is for my own account). And above all of this I have momentum gap cover which should have automatically have covered the shortfall which just was not done on 4 on the last 4 claims. It just seems you need to check all claims as saving is an easy target to pay claims from. Please do not ever top up your savings account as they need no permission to spend this money.