Revision of bot in NodeJS and MongoDB

you Need to modify a bot written in NodeJS and MongoDB. It is necessary to fix existing bugs in the bot and add a few new features.

ATTENTION! Need someone who is really well versed in NodeJS and MongoDB, which when a code will not say "Oh, it's probably I would refuse it, and I'm afraid to break anything".

Budget is up to 10,000 rubles (the final amount of payment depends on the amount of work)
People with the requirement to make a prepayment, please do not disturb.
Or payment upon completed work or payment by instalments (fixed one mistake, showed received payment), or via the system of secure transactions.