I have been dealing with Dexcom as the parent of child with T1 diabetes for a year.
Over that period of time, I have called them probably 20 times. Every one of my interactions with their operators has been positive. I have always received timely help from Dexcom, even when calling in the middle of the night (which has happened numerous times). Every time I have lost a sensor they have replaced it for me, even in circumstances where it might have been user error.
I cannot think of a company in the medical field that provides the level of support that Dexcom provides. They truly are an exceptional company in my eyes. I only wish I found the same level of support with other companies in the medical field.