Dismissal from Public sector bank

Dear sir, As part of allowance i was applying for rental entitlement for a sum of 8000. I was staying in a mansion and paying rent 5800+electricity bill. But i was claiming fixed amount of 8000. Now bank enquired about rent and decided to dismiss me from services. I was just 28. I didn't know if it was such a big offence. I'm ready to rectify my mistake. What can I do hereafter.