I requested a refund using the online form a few hours ago but received an error message saying my email ID was not the one associated with the booking. I sent a screenshot of the error to the local booking office, and a couple of hours later received an automated email saying my miles were being credited back to my account, and the tax amount would be refunded in four to six weeks. That was followed by an email (not automated) from one of the local offices saying more or less what the automated message said, but specifying a much longer time frame for the refund of the tax component - "eight to 16 weeks". Just logged in and the miles are back in my account. That part was quick!