DISCOVERY BANK BAD CUSTOMER SERVICE!!

I have emailed discovery card numerous times for help. Their reply is that they are not replying to emails, but a customer can phone them??!!! What a cheek! I, as a customer, must call them, at my cell phone expense??!! There is absolutely NO REASON that emails from customers CANNOT be answered?! Even worse, they are ignored! Why do they not call emailing customers back, at THEIR EXPENSE???