Interes demanded by bank on npa account after 3 year of recovery

I have some doubt over time barred debt in case of interest not charged on bank account declared as npa, now after 3 years of last payment made toward principal , can bank legally ask for interest on that account not charged previously neither after principal recovered. here is full case my father has taken a cc loan of 200,000 in 1996 against fixed deposit of 100,000 and guarantee of her mother (landlord of building in which bank is tenet ).in 1999 the account become inoperative and declared as npa by bank and serve a notice by advocate for amount per notice bank has en-cashed the fd and rest amount has to be paid along with interest .with mutual consent with manager it was decided to recover the due loan amount from 1/4th part of rent being paid to guarantor of above account .the net balance asked in notice was 99000 .as per available records with bank ,balance outstanding on 1-04-2007 was 118000 and statement shows that 1/4th part (rs 1865)of rent was paid in cc- account . which continues to be same till [deleted]. on [deleted] without any information to us ,bank written off the remaining amount of 53000 with left over at rs 100, .however rent continues to be short received in guarantor rent account by the same amount till [deleted](amounting rs 70000).after 2013 full part of rent being credited to rent account .now on feb 2016 bank manager called us and told that the 53000 rs has been written off against your account and is payable by us else they will deduct it from our rent account .on scrutinizing the bank statements of both account i came know that total of rs 138000 has been short paid to rent account against loan of rs 118000 .on discussing with manager ,she told me that after 2010 you loan was transferred to suspense account and same done with that 1/4 th part of rent account ,which set off each other with remaining cr bal of 17000.on asking her how to settle this account she said rs 59000 (interest from 2007 to 2013 )has not been charged and same has to be paid by us ,for that we have to offer an amount for one time net settlement of this account.on asking give details of calculation of interest ,she handed over a sheet of calculation of contractual dues showing net due of 103000 {compound interest from 2007 to 2016).as asked by manger we gave an offer letter for settlement at amount with in 15000 stateting our poor financial condition and medical emergency of landlord .but on consedering with their r.o no settelment would be possible as per their policy one time benfit can only be given if borrower has no income source and in this case rental income is there and hence full amount is payable . so i want to ask your opinion on following questions 1.can bank write-off an npa account without any notification in case where regular recovery was been made and further recovery was clearly possible . 2.after 2013 when principal was fully recovered bank should have charged interest and asked for same .but instead they waited till 2106 to increase the amount of interest and try to recover it now .note that no notification was sent between 2013 to 2016 for any amount due. i want to know would it be case of time barred debt . 3. if its not case of time barred , will i be liable to pay interest for period between 2013-2016. 4. bank has only verbily asked for due amount and no written notice of any amount due has been given .when i asked them to give notice in written for due amount they refused to do so. please guide me what action should i take .contact @[deleted] whatsapp only.