Originally Posted by Often1

Calling is the worst way to deal with issues which require research. It is inevitably faster to send in a mileage request using the webform. Note that if your request relates to segments flown on other carriers, those can take 2-3 months because some partners use email rather than electronically linked database. Additionally, if the credit you are seeking is for a flight where you for some reason weren't scanned onto the manifest, it can take forever.

But, whatever you choose, calling is the least effective means because all you are doing is speaking with someone who is filling in their version of the form you could have filled in.