Society in general has a real problem. Customer service as a norm seems to becoming increasingly bad. Sorry you had that experience. Hopefully Insulet learns of this employees shortcomings and repairs them soon.
something similar happened to me, they put my order on the wrong card, and when I figured it out, I called them and they switched the money to the correct card with no problem.
They are human, could have been a bad day for the service guy you got. what mattered for me is that they got things fixed quickly. so in the end I am still happy.
any other problems happen to you, besides this, to make you think the service is going down?