"(Indians tend to speak good English, it can be the accent that some people, especially the elderly find difficult) "
For me its the SPEED of sub-continent English that is the problem - and of course the stress is different. I'm not asking for "Loooooooo-eeeeeeee-zzzzzzzz-iiiiiii-aaaaaaa-nnnnnnnnaaaaa" but a little slower would help. The clearest help I ever had on an international call was from Estonia and, very oddly Afghanistan (tho I guess if you're country s invaded every 30 years by assorted Anglo-Saxons......)