I played for a while and just got to b-rank. I left and rejoined and now I only have the stuff that I started with(iron armor, iron pick, iron axe, steak).
Prison was reset not too long ago. https://www.minetime.com/threads/prison-reset-date-features.19025/
The prison server reset about 1-2 hours ago, everything reset but I don't think another reset is happening in the next few months.