Not sure if this is your issue but I read somewhere (probably on the wiki @ pinataisland or in this forum) that you need to meet the unblock requirements in the same garden as you first met the appear requirements for the blocked species. Only an issue if you have multiple gardens but for example if your Eaglair first appeard in Garden 1 you need to get 5 Elephanillas in Garden 1 and not any of your other gardens. If you did meet the requirements in a different garden, just box them up and unbox them in the garden that you need them.
You can also read the wiki article here for help.
Zune profile: Hobbess254
