By that time what will happen with the banking process if there happens a termination of internet connectivity for few days time.
First, that's highgly unlikely in developed countries.
In the same way that the power can go out in a neighborhood of a city for a few hours, the same can happen with the Internet, but do not expect a massive blackout in all countries for several days and, even if that were to happen, the blockchain would still be there. The scenario you raise is so unlikely that I don't worry about it.
I agree with this. Developed countries had always countermeasure regarding on technology that helps us in our daily life since it has been a great progress and had a great impact in these present time. Hence, some countries that belongs to third-world country may experience those slow connections and it's inevitable.