some orders are missing VAT amount?

Hi
I need some serious help please, i have setup paypal express checkout and its working bit strange, it is collecting money for me and getting orders confirmation BUT problem is some times i get orders with no VAT added to them, i have all the products subject to VAT, so i should receive money for example
net price £100
shipping £10
VAT 16.50
Total £126.50

some orders are working fine and some orders are missing the vat figures and from above example i a only getting £110?

Whats going on please some one rescue me?
Regards

Hi,

Did you get this error sorted because I've just had a similar thing happen.

A customer purchased from Ireland and Tax was not added when he checked out. Paypal Express.

I logged in and tried checking out myself with the same product and an Ireland address but this worked fine.

Seems that ZenCart doesn't like tax and also paypal is riddled with occassional errors.

Wish I could find a reasonable Merchant account service.

Anyway just wondered if you sorted your problem then I could pick you brain. Cheers