BOGOS: Free Gift Bundle Upsell

Have used the app for many months but as a result someone called Luke Bendall has been able to fraudulently order our GWPs and only pay for the delivery never for any product. Last year it cost me £1000s as he was ordering 25 of each product and only ever paying for delivery. I don't how this has happened but it seems to be linked to how the app creates a 100% variant. I removed the app and this stopped but used it again for the first time this weekend and spotted an order from him again. Please beware, would hate for this to happen to someone else.