I recently started playing TBC Classic, and when I was going pay my subscrition there was two accounts available, one (EU) and one Wow1(EU). As there was no apparant and obvious indication of which account was previously used I had to just pick one. In the beginning this was not a problem as I had never played TBC classic before therefore no characters were missing.
Today however I installed retail wow only to find out none of my characters were available. Attempting to write a ticket on the issue only to find out it is not possible in any way, shape, or form to merge the two accounts. One account with only TBC classic characters and one with only retail characters. And the suggested solution is getting a refund on the subscription of one account, then I will not have the TBC character which I have been leveling with my other friends.
I have seen other threads on the same issue where the suggestion is going through your previous payments and such. That seems very unnecessary and anti-consumer. As I do not even have any memories of creating another wow account within my Battle.net account.
So it seems like I will not be playing any retail because of little to none clarity on the Battle.net client.