I Am 73 Tears Old, And Have Taken Amphetamine/dextroamphetamine For

I am 73 tears old, and have taken amphetamine/dextroamphetamine for 25 years, 60mg a day, 2- 10mg tablets at 7am, 2 at 11am and 2 at 3pm. I sent my prescription into optumrx and was advised that there is now a quantity limit of 2 tablets a day, and they have denied my request to cover the 6 pills a day I normally take. They have previously covered my needs for the past 8 years, and I had no notification of a quantity limit being placed on this drug this year. Any suggestions?