I have exactly the same problem, and having read through the forum it would appear that this is a fundemental issue with XML-sitemaps.
I ordered the software on Sunday, PayPal receipt number 4802-0824-5873-7939, email paypal@rbis.eu and no download link turned up.
The link is not, I repeat, IS NOT, in my spam or junk folder, it was not received.
In addition, all emails that I have sent to XML-sitemaps have been bounced back with error messages relating to messages not being delivered.
On top of all this it was a monumental fight to register and access this forum - I have lost count of how many error messages I have seen during the registration process (which has taken a total of 5 days to complete).
You need to sort your act out XML-sitemaps, and whilst you are at it, please send me the WORKING download link for the product I purchased last Sunday.