Disappointed!!

I have been diagnosed with Bipolar mood disorder. 2 months ago i started taking the medication Rexulti 1 mg. Gems authorised it. However now all of a sudden they have declined the medication. My body has become accustomed to this medication as it has started to work. Now does it mean I must stop "Cold Turkey" as I cannot afford to buy it on my own. I'm not sure how to handle this. Please be weary of situations like this. Writing here is to benefit the communities as GEMS doesn't reply to any messages put in here.