They changed up their claims department (outsourced it maybe? not entirely sure) along with the entire customer service department on September 1st last year and many providers have been unable to get paid for services rendered, negotiate rates, or even use their billing system since then.

Their phone system even has an automated message set up for it... "If you're calling in reference to claims prior to September 1, press 0. For dates after September 1st, press 1".