Solo Unwanted Owling

Merciless Sister,
I exactly know that your day was really boring and sorrowful but if you encountered something worse you can just mention it in short but only at last of your letter, understand? I actually understand heart to heart that you don't have any friends and dearly want someone to stay with you at such a difficult and new environment and you need not worry about it because I am here now. But you surely do remember about the promise you made before boarding the Hogwarts Express, don't you? Did you literally forget to write me a letter after all these days?! If it's because of depression then I might excuse you but however, how can you forget your one and only sister? You know what, this is an early sign of the beginning of the cunning and unfaithful frenemy relationship between us. You might be shocked about this fact but I can't help it as it's quite reasonable. I did so many things for you to make you a lovely daughter of my mother, yet you always tend to forget me for no reason at all. I often wonder the problem with you which keeps you so much occupied, after all. Right now, you should remember who I am, I am the one who can make your life a living hell with a flick of the light switch which brightens your gloomy night. Even though you don't use a light switch there, you can just consider it as a flick of your matchstick or lamp or whatever reasonable for the time being. Yet you have the guts to do something like this, really unbelievable. Being a generous sister, I am forgiving you only for this time. Write me a letter quick about hogwarts or don't you dare come to my house for the Christmas holidays.
P.S. Mom has send you a parcel filled with chocolate chip cookies along with this letter as you already see. I guess you already opened the parcel too. We don't need them anymore to be honest, they are totally overcooked and broken. Try ignoring the black burns on them, it's nothing to block it's unique taste and be thankful to us for wasting our precious time and money in this.
Yours,
Amanda Ortiz