This is my constant nightmare with all supplies. We all become hoarders. I am with BCBSKS now and they have been accommodating. I was with UHC for 2 years before this and they stunk! They would only send 1 transmitter at a time.
I can only recommend restating your sensors to give yourself a cushion. I currently have a 2 sensor cushion from restating my sensors. I know that folks here have restarted their sensors and get an additional 10 days (20 days total from 1 senor. I typically get another 5-6 days.
Here is the link about restarts. I use a guitar pick, it is so easy.
https://forum.tudiabetes.org/t/a-little-tip-for-removing-the-g6-transmitter-for-restarts/81800/38