You can log in to the Income-tax e-filing portal and make a Refund Re-issue Request. However, this works only if you did not receive the refund cheque and it was returned to the Income Tax Department.
Yes. You can do this on the Income Tax e-filing portal, on the 'Profile Settings'. That is where you will find the 'Update Contact Details' section.
Your correct bank account details must be provided in your TDS Certificate. Otherwise, any discrepancy might result in a transfer of refund amount to the wrong bank account.