The level 25 bree horse, according to LOTRO/VALVE customer support, is bugged and many people who should be getting the horse will not find the necessary bree-steed receipt in your inventory or bank.
Response from support is that you will have to wait until they fix the bug or level 35 whichever comes first. Merry Christmas, Happy Holidays and Happy New Year. (insert sid vicious concert comment on why they were not playing more than one song--PAIN--in the last USA venue.)
Question: Why arent the GMs putting the items in your inventory as complaints come up? Answer: I dont know, ask them.