Problem when making payments: Credit card

I used to be able to choose how to apply any amount paid over the minimum payment so as to pay off a promotional balance before the interest retroactively applied. Now Best Buy has removed the option and made it a 30 minutes plus process by forcing me to call their terrible customer service line. By not even allowing even a proportional amount to be paid to the promotional balance, they are deceiving customers into thinking they can pay the amount off before the term expires while allowing the full balance of the purchase to accrue YEARS worth of interest. This is extremely deceptive and designed to steal from borrowers.