If you write the name of both girls then it will be easy for me to advise. Anyhow talk to your best friend who not talking to you.
Just tell her that what is the problem & it is said in hadees that a Muslim will not be angry with other Muslim brother or sister more than three days. So please let us sit & clear our anger.
The day you do this, pray & ask help from Allah. Inshallah you will be again friends like before. Then let me know