Advice on HV battery death after small accident

Hi everyone,

Thanks so much for ANY advice you can give me. I'll try to keep is short and sweet. ....I have a 2005 Prius and I wrecked it about two months ago hitting a trailer in front of me. It was ugly but no bags deployed or anything so I thought it's fixable. I was quoted $5,000 from a collision place and decided to go cheaper. Long story short I went with someone on craigslist that promised the world. Regardless, when I got the car back a month later it was a BAD fix. The blinkers didn't work and I got the big ! warning lights on. For weeks after the accident I never had those lights. Not sure the source but basically my main HV battery is bad after taking it to a "normal" mechanic. I'm wondering how this may have happened? I believe it sat for weeks before the person started working on my car, could that have drained it? Could the accident have dislodged something making it die? Or is it just coincidence it died shortly after the accident? My main mechanic wants $3,000 to replace and I just can't justify it. Anyway, thanks. I'm at a loss of what to do now since it's slowly becoming a money pit for me. Not sure when to throw in the towel. Thanks for any idea what may have caused the main battery to die and if it's related to the accident. Thank you!