Helloo!!!

my files have been encrypted!
files have .549anBM1 file extensions now and I cannot open them for some reason. Can you help me out? I also found a HOW TO DECRYPT FILES.txt file on desktop which says I need to write to avastvirusinfo@yandex.com. Should I write to them? Will they help me to recover my data? Or should I not trust hackers? I desperately need my files!