My Dexcom 6 system pairs with your Apple Phone, it delivers a message when one part of your Dexcom 6 needs replacing (sensors, transmitters, etc.) Three weeks ago, a message said my transmitter would expire in three weeks. However, when I try and reorder, a message says there is a problem with my account but no phone number or email to remedy the problem. HELP! User's recommendation: I was happy with them until this problem occurs, beware, only recorded messages are available and no human to speak to when there's a problem.