Fill out the Business Tax Refund Request form when you need to get money back from the City for an overpayment. You may file a claim for refund using CDTFA's online services.To submit a claim for refund, simply login using your username and password. To see if you are due a refund, please click on Refunds and complete the comment section advising that you are inquiring about a refund. I overpaid my business tax. How do I request a refund? If you believe you have overpaid an amount and you wish to receive a refund of the overpaid amount, you must file a claim for refund with the CDTFA. Students will generally receive their direct deposit refund 5 to 7 business days from the date the refund shows as processed on the student account. A. Fill out the Business Tax Refund Request form when you need to get money back from the City for an overpayment. Online: Schedule an appointment 5; Phone: 510-622-4693; Office Address: 1515 Clay Street, Suite 305.