What if adding to basket works but checkout fails?

[rm29-mis]

Say you add to basket but the purchase fails for some reason like traffic to the website or random volatility due to too many people trying to buy etc.

In the 'CheckAndBuy' try loop you may run in to a situation where you attempt to add to the basket multiple times and there is a block on multiple additions to the cart so it fails in this loop from then on.