Faulty CO2 Detector and Misinformed of Upgrade

Bought my original system 12/24/2017 with a promo package and also it allowed me to add additional sensors, keypads, etc.. for the needs of my home. Spent almost $1k+. I have made my monthly faithfully every month since with out fail or interruption of service. On 1/11/2021 I called as my CO2 was beeping and fault light was stuck on. Even after changing batteries, then calling support whom told me it was faulty after troubleshooting. I asked them to order a new one, where I was told my system was obsolete but I was eligible for a free upgrade. She had me count all my sensors, keypads, equipment, etc.. I was told I should have it within about 5 business days. Today is 2/27/2021 and no system. I look on my account and see they typed in the order and it says fedex but no number. I call Simplisafe and then I am told I was told wrong information and they would only upgrade whats was in my original package. I said great thats all I want. She said no, that meant "Starter" which included a few sensors and some equipment. However when I bought this it allows you to buy and add on. So now they want to me to buy all my equipment essentially over again? This make no sense. To add the rep then states but your CO2 detector is only out of stock. WTF, so this whole time due to error if that on Simplisafe my home has been unprotected from CO2 warnings when it could have been already here and or do what you stated and upgrade my system. This makes me now want to shop around and I may pay a bit more a month but it maybe worth it.