Your friend invited you to his birthday party but you could not go. Write a letter to explain to him why you couldn't go even though you promised to go

Hey (insert name), Sorry I could not make it to your birthday party today. I was busy and had some places to go and I was not aware of them until today. If there is anything I could do to make it up to you, please let me know! I bought a gift for you that I will most definitely give to you the next time I see you. I hope it is enough for you to forgive me for not going. Your birthday party seemed so cool to look forward to but I’ll try to make it to your next one. Happy birthday and enjoy your special day by the way. Sincerely, (Name).

The last one is right