My husband is a General Contractor and purchases the bulk of his material at Menards, especially during the 11% Rebate offer. I personally have mailed thousands of dollars worth of rebates and have never had a problem.
Likewise, there has never been a problem cashing them in either. If, as the original poster wrote, you submitted the rebates to 2 different P.O. Boxes, then therein lies the problem, IMO. It should be sent to the P.O.
The only other rebate address I have ever used for the Menard's rebates is the special General Contractor rebate form, which is sent to a different address. Menards is the easiest and most reliable rebate program I have ever used.
Product or Service Mentioned: Menards Rebate.
Reason of review: Love the Rebates!.