If you received a 4883C letter, the IRS is stating that it will take about 9 weeks to complete the processing of the return once you have verified your identity. You can also find that information here Understand Your 4883C Letter. Some have reported getting refunds sooner but that will not be the case with everyone. It all depends on how quickly the IRS finishes processing the return.
If after 9 weeks you don't hear anything, you will call them at the IRS tax refund hotline at 800-829-4477, Monday - Friday, 7:00 a.m. to 11:30 p.m. Or, call the 24-hour assistance number at 800-829-1040.