Dollar Tree review: coupon

Hello sometimes I take manufacturing coupons from Sunday paper and the coupons have no exclusion that's mean are used easily at dollar tree because I see people on YouTube how they use them unfortunately they don't allow me using any coupons I ask how the store manager say automatically is scanned I tell her other use the I see them on YouTube they take them she say you shouldn't believe anything things you see yesterday on my way I stopped at different locations the cashier took the coupon but in different way so I feel lm discriminated for them not talking my coupons just I wanted to bring this to your attention this way you have some ideas how people are treated at dollar tree