I'm so sorry this happened to you. I don't have any good advice for doing with your so-called friend (unless you need advice on how to give a beat down) but I do have hair advice. (My auntie owns a salon, and I've picked up a lot, and with short hair myself, I've been able to have temporary long hair with some assistance)
Once you get your hair fixed, if you're still missing your length, you can get extensions. You have several options, but I recommend clip in extensions if your hair is not very thin. More permanent extensions can be painful and pricey, and worse, damaging to your hair.
If you're thinking of going with regular long term extensions, I've seen straight haired girls have the best luck with sew in extensions, but it can get pricey. The glue in ones can ruin your hair, and are still hella expensive, and the tape in ones are shorter term, but still expensive.
I reccomend going to Amazon or your local beauty supply store and getting clip in extensions (see link below for example). The options are great, from synthetic to human hair, and they come in plenty of colors and lengths. I recommend individual clip in pieces versus a long clip in unless you can match your hair pretty well. I feel with the individual clips you can blend them into your hair better so they look less "fake" (Trust me, no one else can tell, but you)
Synthetic hair is cheaper, but harder to style. You can't curl most synthetic with heat, and it can get really frizzy fast if you're not careful. It can take some special care, but usually wears pretty well. Human hair extensions are expensive, but wears and styles just like your hair. You can even dye it.
My recommendation, if you want to try clip in extensions, is to try some cheap synthetic ones before you decide invest in human hair ones.
(ROSEBUD Clip in Hair Extensions REMY Human Hair 8Pcs 18 Clips Set 14-22 inch https://www.amazon.com/dp/B07NWDKRTK/ref=cm_sw_r_cp_apa_i_Be1rDb7GPNVSF)