First Alert Combo Smoke/CO - unable to connect 5 devices

Within the last 2 months I purchased and setup the Ring Alarm System and 30+ various sensors, cameras, smart-light devices and set them up successfully. However - I've purchased a total of 5 First Alert ZCombo (Gen 2) spoke/CO detectors and I was not able to get a single one setup successfully. I contacted First Alert support and I was directed to Ring Support. Support had me start with a fresh device and was unable to add it nor remove it successfully. I was moved to tier 2 support which specializes in First Alert units and they were unable to proceed as well. All in all 1hr 38 minutes of phone time troubleshooting the installation and without success. As a result, I'll be sending the units back. Finally, I'd like to add that the customer support experience I received was poor. The representative was uninformed, impolite, and when the call disconnected on his end, didn't follow up with the phone number provided to him (as asked to call back for disconnection). The overall experience demonstrated to me that Ring's customer service department is lacking in overall quality control necessary to promote good experiences for customers. It's a shame because product's technical development is amazing, but following it up with rather poor customer service really sours the entire experience. For me, this was very much a let down. I reached out to Customer Service on Ring's Twitter account to share my experience and received a highly impersonal generic response. The CS agents I spoke with were: Blade and Joseph.