Hi,
If you have entered a space or a bracket or a '+' sign before the country code 91 such as....
'+91 xxxxxxx' or '+91xxxxxxxxx' or '+91-xxxxxx' or '091 xxxxx' or 091-xxxxxxx'
then try removing the space or the plus sign in the number and enter it as
091xxxxxxx and try to complete the verification after clearing the cache and cookies of your browser.
If this still doesn't work, report it to eBay as there may be a bug.
Kind Regards,
Mustufa