Okla. Admin. Code § 710:50-3-7
If a refund is not processed in a reasonable amount of time, a duplicate Income Tax Return should not be filed until the taxpayer is advised to do so by a representative of the Oklahoma Tax Commission.
Amended at 15 Ok Reg 2811, eff 6-25-98
Amended at 18 Ok Reg 2810, eff 6-25-01