RE: my bot stopped working in telegram, help

Did you enable groups for the bot?

use @BotFather, send it command: /setjoingroups

check the bot's privacy mode,

did you add the bot as an admin of the group?

See also,
https://stackoverflow.com/questions/37338101/how-to-add-a-bot-to-a-telegram-group

and,
https://stackoverflow.com/questions/37243303/telegram-bot-doesnt-respond-in-group-chats