I am hoping that you mailed the tax return by certified mail and you have confirmation of the delivery.
The amount of refund has no bearing on the timing of your tax refund. I would advice you first call the IRS at 1-800-829-1040, or 1-800-829-0922 to speak with a Customer Service Rep and determine the status of the refund.
Alternatively, you can access the IRS website Internal Revenue Service
and click on link "Wheres my refund?"
, and follow the instructions on this site. Enter your personal information, the website will inform you of the status. Non-Filing of prior years.
The IRS will inform you via a letter letting you know what the hold up is. If you have not filed a tax return for previous years and you have taxable income, your refund will not be sent to you until such time that you file those delinquent tax return's. The filing of deliquent tax returns will release the refund subject to you not owing any taxes on those past tax returns. If you do owe prior year taxes, a deduction would be made to account for past liabilities.