You can reach Authorize.Net Customer Service directly, dial (877) 447-3938. Please be sure to have your Gateway ID number available when you call.
** Please note ** When contacting Authorize.Net directly, you will require you to furnish your Gateway ID number (G.I.D.) for verification. To find your G.I.D. Number in your Authorize.Net Account, please follow these instructions:
> Log into your Merchant Interface Profile at https://account.authorize.net.
> Under Account, Click 'Merchant Profile' in the main left side menu
> Find the Payment Gateway ID listed under your Merchant Name near the top of the page.