Seeking Advice, energy company bankrupt after freeze

Wondering if anyone has dealt with something similar. My energy provider, Brilliant Energy, declared bankruptcy after the freeze. I was moving shortly after the freeze and have been calling them (no answer), leaving voice-mails, and leaving messages through their in-website customer service emails, about moving out to cancel my service. Well I moved out, never was able to reach them. I have a large bill it says I have due on their website. I canceled the automatic payment, but how do I really cancel my account? Will they keep trying to charge me, affect my credit? Any advice? Thanks!