35 Miss. Code. R. 4-07-03-601
All manufacturers and custom processors, with certain exceptions, are required to obtain a Direct Pay Permit for purposes of reporting and remitting the sales and use tax applicable to purchases or rentals of tangible personal property, utilities, with the exception of telecommunications, and services to the Department of Revenue in lieu of paying the applicable tax to the vendor. If a permit holder continues to pay sales tax to the vendor rather than remit directly to the Department, then the permit holder will be required to contact the vendor for a credit or refund of any overpayment of tax; this will be required in all instances, even if the overpayment is discovered during a sales or use tax audit where an assessment of additional tax has been made. No refunds or overpayments will be allowed beyond the Statute of Limitations as provided for in Miss. Code Ann. Section 27-65-42.
35 Miss. Code. R. 4-07-03-601