Apple Pay

Everytime I try to pay with Apple Pay in stores like subway and target etc. on my iPhone X it always says unable to accept and I do have money in my Apple pay so I don’t understand why it declines. I’ve searched how to properly use Apple pay with iPhoneX and I’ve done it step by step it’s not hard it just never goes through and it’s a hassle I have to transfer to my bank to use the money and take 1-3 days. Please help!!