Q: Debit card details wont update on my visa debit card which has money on it

IM experiencing a fault with my billing details, ive tried and tried adding my visa debit card details over and over with EXACT details and it keeps declineing my details, ive made purchases last weekend with no trouble at all only now when i tried redownloading a purchased app its prompted me to re do my debit card info, my apple id still works but that ******* card wont approve help!!! Ive been going crazy trying to sort this out!