What to do if i don't get NOC from bank while appearing for other exam

Sir, I have been working in a bank for last one year. I applied for SSC CGL2017. I informed my managers about this and gave an application for prior permission/NOC. I didn't take it's receiving. The application was later sent to rbo for permission through competent authority. A month later I got a call from RBO that for applying you need not take NOC,but when you will take the exam, you need to take the noc. During tier1 of cgl, I gave my manager in written that I am going to take the exam but they didn't send the letter to RBO and now I'm about to take tier 2. My query is that if I'm finally selected, and SSC asks for NOC, will my bank issue me the NOC. if not, what are my legal resources. However, in CGL 2016, SSC didn't ask for NOC. If I am finally selected, and before joining the new organisation, if my tender resignation, will that suffice. If ssc does not ask for noc, and I clear all the stages. Can my bank create problem at the time of resignation?