I hope you have better luck henceforth. My son has been using Dexcom for seven years, and G5 is by far the best iteration yet. By far.
He does not experience the outages like you have described, but certainly if water gets bt the transmitter and the sensor, like after a shower, ??? can result. You can remove the transmitter and dry things off and then put the sensor back. I have done that in this situation and found it to be helpful.
Good luck!
They donāt recommend it but yes. Last time I had one replaced thatās what I did. Kinda awkward getting the old one out without detaching things.
NEVER. Thatās the whole reason this community exists! 
Yes, returning the old one is a condition of replacement, so even though he didnāt mentioned it you should go ahead and return it. Somewhat confusingly their standard RMA packet includes a thing like a urine test container and a hazardous waste envelope. Apparently the FDA or someone insists that they treat transmitters as having been in contact with bodily fluids even though itās completely separated from anything that pierces the skin. They donāt refurbish themāIām sure the FDA would have a coronaryābut having worked for a biotech instruments firm I assume they run a diagnostic on it to see what went wrong and improve quality control.
Thanks for the info @DrBB - and thanks also @Lorraine. I think Iāll wait on trying to change the transmitter while wearing the sensor until I have a little more experience with these - I donāt think theyāll keep sending me new sensors and transmitters indefinitely 
!! I must say that Dexcom has been great about sending replacements - most have arrived overnight. So very pleased with that. Thanks again! I appreciate all the help. Gracie
Did you keep the safety lock from the inserter and use it? Iāve been making a habit of keeping mine rather than throwing it away just in case I have to take my transmitter out. I donāt know if itās actually going to be of help or not, or if Iām just making my life difficult by keeping this piece of plastic around that my husband keeps asking āWhatās this?ā every couple of weeks when he stumbles across it.
I thought about it but I never figured out how to use it for thatāafter the first few sensors I gave up trying to make it work and ever since I just pry the tabs apart with my fingers. More awkward when the sensor is still attached and on your upper arm, though. I suppose thereās a video somewhere of what they have in mindā¦
Yep. Demo at 1:15 minutes in. Though it would have been more helpful to turn it the other way. Iāve used the lock successfully when the sensor and transmitter are on a flat surface. Itās somewhat easier for me than prying the two tabs open as Iāve had surgery on both hands within the last 6 months, but I can also just hand it to my husband to pull out, too.
Iād sing the ABC song a few times. Quick stop/starts of the receiver have been picked up by Dexcom as re-use of the sensors and they may deny assistance with bad equipment if you call them.
I have had ONE sensor go bad since I started using my Dexcom February 25th. If my sensor is a week old at night, Iāll turn off the sensor overnight so I can go to bed and restart it in the morning.
During my last call, the Dexcom tech rep said she could see the number of times there was āno serviceā from my sensor.