trying to buy the last expansion I get this error here:

PURCHASE CANNOT BE COMPLETED
We’re sorry, your purchase cannot be completed. Possible reasons for this may be:

You have previously purchased the item.
This purchase cannot be applied to your subscription(s).
Offer is no longer available for purchase at this time.
We are currently experiencing technical difficulties.
We are currently performing maintenance.

I have already done everything possible, cleaned the cache changed various browsers in the end I formatted and reinstalled windows, no luck. In another pc too, then I used windows 7, nothing to do, that error message always appears.
I changed credit card, deleted it to pay with paypal but even with paypal half of the popup appears without being able to enter the zip code.
Moreover it is 15 days since I opened a ticket no response at all.
Is there a way to get help or not.