Is it normal pizza place does this?

a pizza place near by put coupons for a free mini pizza into my school's newspaper. I got several of the coupons and then called to place an order, but they said that the coupon was only one per person, to which I responded, the coupon didn't say that, so she asked her manager and she said the coupons were printed wrong, to which I responded, regardless they say free mini pazza, and don't have any other conditions attached, she then said well that's how we do it, so I told her that's false advertising and it's illegal. After this she called the owner and then told me thay'd do the order this time but not again, since they donated the coupons it is there discretion whether or not to accept them, I canceled my order because at this point I was afriad they'd spit in my food.

I know for a fact that they are wrong, the printed coupons are legally considered an offer to a contract and by using them I'm accepting, they can not legally do what they did.

I know that every business wants to save money, but they authorized these coupons to be printed and did not put any restrictions on them, so is it normal for them to be so difficult.