Pnp asap double debited/ uncleared funds

I used pnp asap yesterday and they charged me an initial amount and a final amount. The initial amount is stuck as uncleared funds so it's like being double debited. This is not the first time this has happened when using the app. I thought they would have fixed this issue by now. Using pnp asap is a gamble. I will not be using them again. I also cant get through to their customer care call centre. I have emailed them and got no reply. This service is supposed to make life easier not harder. Very disappointing.