Will the mystery person show him/herself?

Yesterday afternoon my colleague brought be a huge bouqet of roses, a birthday balloon and a cute white teddy bear. The note read "Dear Cindy, Happy Belated Birthday! I hop you had a day as beautiful as you. Sincerely, Your Friend."

"Your Friend"?!?!
Who could it be? The wording made me think of someone who left me a voicemail the night before, wishing me a belated. It wasn't this friend.

Who? Who knew it was my birthday but after the fact.

Ok. Whoever sent me I have this to say...
1. Thank you. They were lovely and so unexpected.
2. Please, please tell me who you are so I can thank you.

It's so annoying not knowing.
It's like when someone tells you that some boy likes you but the actual boy won't ever make it know. Hate that.