Michaels Stores

I received a $5 coupon after I signed up and downloaded the Michaels app. I wanted to use it towards my purchases in store but the cashier couldn't apply it. She asked her manager to check it for me. Without even looking, the manager said it did not come from Michaels website. It came from Michaels website and I didn't create this rewards! After I showed her where it came from, she said it was not going to work. She was rude and was not willing to look into the issue and was not willing to help at all. I'm not going to shop at Michaels anymore and I'm trying to delete my online account. Also, I will make sure my friends won't visit your stores anymore.