I have got the same explanation a week ago. And I prefer no explanation at all, because when
I get such explanation I get the feeling I am just fooled...
I guess they have problems in the store software (may be throw some third party shopping card service, I do not
know what they are using). They should be able to see all transactions, so I do not know why the service center can not just add the product manually once called.
In any case, CW admins there will solve it soon.
PS. 3 more posts and I am prepared for X4 upgrade with PayPal