It is appreciated that you have resigned your earlier service before you joined to the PSU Bank. If in your resignation letter, you did mention your intention to join the PSU bank after resignation from IT sector, then you now may request your past employer to treat the common period of service i.e. 3 months as any kind of leave without pay (if internal rules permit that) or else the period may be treated as foreign service . Moreover, if you have drawn payment from both the services then it would be an offence, so, in that case refund the payment received from past employer as soon as possible with interest.