TD Bank Credit Card Complaint

TD Bank Credit card department,

Transaction issue Florida

I used my Target M/C red card which is supposed to get me a 5 % discount on target purchases. I made a $23.00 purchase on -/-/2015 and they only gave me a $0.00 credit and said it is 5 %. I also noticed that they are not collecting the correct amount of tax which is 6 % in Florida as they only taxed $18.00 of my cat food purchase of $23.00. I suspect this has happened on all of my target red card purchases for the past 5- years.