CVS Arm and Hammer Deal

Hi All- I went to my local CVS to get the Arm and Hammer deal Buy one Get 2 Free. I had 3 MF coupons for $1 each. They would only let me use one. I read a lot of blogs were people were able to stack 3 MF coupons but my CVS would not let me. I even showed them the CVS BOGO coupon policy, (I printed it out and brought it with me). There response was that only one is allowed that is why the register wont take it. I would like to know others experience with this deal. I also used a $5 rewards on this purchase. Would have been a .14cent purchase had I been able to use those 2 MF coupons.