How many tests are you doing a day? And how many injections are you doing a day so far? The best thing to do is to inject large amounts but don't drink or eat anything with sugar or carbohydrate in until there are signs of the bloods coming down. Failing all of this, get down to A&E where they can put you on drips to purposely bring the sugars down. They will eventually starts responding.
I have personal experience with this, went to hospital and was out the same night as they had reduced them for me. Some peoples systems only respond to highs.