tax treatment of iinss-bond

Every year on accrual basis you have to show interest and when actually received that account will be nullified.

Show it now as prior period item and rest of current year

Show it in current year and the part which pertains to previous year show it as previous year prior period item rest of current year show it as normal receivable

If you are not under Audit clause then no need to show prior period item separately

Just show in your books and in ITR show it together