Don't remove your pump the night before.

You have no long acting insulin in your body and will become ketotic before the surgery.

Contact your endocrinologist ASAP.

What probably happened was the person who contacted you looked at a list of medications that said diabetics should stop taking medicine the night before.

I operate on many Diabetics and the only ones that I tell to stop taking insulin the night before are type 2 diabetics, and I don't always do that. Type 1 diabetics I would have skip their morning injection and have them take the long acting after surgery. Type 1 diabetics on an insulin pump I would have keep their cannula in and unhook the pump just before surgery.

If there is any question at all, I would call the patient's endocrinologist and do what they suggest.