Hi,
I don't feel like i can be of great help as the only medicine i get on prescription is insulin, but didn't want to see your post left unanswered.
I don't understand why they would take januvia from your prescription, not only without notice but when your BG's are rising..
My advice would be don't wait for them to call you, call them, call your GP and your specialist nurse. Failing that make an emergency appointment monday to see a GP. The emergency being you have had medication removed from your prescription that going without is affecting your health.
I'm not sure if they can actually do this or not, hopefully someone else can answer that for you so you know where to start on Monday. I do hope you get it sorted though!