I am having an intermittent problem with my store, two successful orders just today followed by one that got charged through Paypal but no record in the store at all

I am using Paypal IPN and all other modules that aren't being used are not installed

The first time this happened was right after I installed Simple SEO URL's and uninstalling the Paypal module and re-installing plus activating the PDT Token fixed that

I am at a loss as to why I can have several successful transactions and then one like this out of the blue....and this one just bites, a large sale by my store standards LOL and I have to refund it now with no way of knowing if the customer will bother repurchasing

I have logging switched on so I am going to go through those to find the ones from today....could take me a while LOL there's lots there