Subway complaint: Not honoring coupon

I visited this location on 06222022 with A coupon for A ‘6 combo meal for $5.99. When I arrived at the counter before placing my order I presented the coupon to the counter person and asked which sub can I get with this coupon and he responded and said any except for (2) i cant recall which ones he stated. Nevertheless I wanted the Italian sub and told him that I wanted it on wheat. he made the sandwich and once I got to the time to pay he told me it would be $7.85! And I asked why that price and the coupon was for $5.99. And he pointed out a couple of printed notes with some scribble gester and said we dont honor the coupons and instead something about 20% due to the cost of food. I asked why was’nt I informed of that when I presented you with the coupon before you started my order,and he said there’s notes posted everywhere. I came for A sub not to read signage that did’nt match subway decor in any form so I was’nt paying any attention to the pieces of paper taped on the glass. I reached out to the franchisee and the remark was… They had A choice to either honor the coupons and go out of buisness.. Or not honor them and maybe survive a couple more years. And this is how Subway is being represented.