Can I wear my plastic retainers after not wearing them for 5 years? My bonded wire broke while flossing.

Hi, I had my braces taken off 5 years ago. I have a bonded wire retainer on my top and bottom teeth. I also have hard plastic retainers that I've never worn. My wire broke on my top teeth while flossing. I tried my plastic retainers on and they are somewhat tight but still fit. I cannot get an appointment with my orthodontist since they are closed (corona). Can I start wearing my plastic retainers? I'm afraid if I do nothing that my teeth will shift especially the top. Please help. Thanks