Moved house and now my Gen 1 motion sensor and contact sensor won't work

Hello,  Bit of a long post (apologies). I recently moved house and brought my 1st gen motion sensor and contact sensor with me, which worked perfectly before I moved them. I set up a new location for my address and deleted my old address. I managed to set up my old Ring Alarm base station fine and connect 2x new cameras to it. However, I can't either sensor to connect.  Motion Detector Gen 1 - it shows up on my Ring app under my dashboard "ring motion sensor 31346 is offline". I've put in two different batteries which both work in it. On the 'Connect Your Devices' page it says that I should pull the tab on the back of the sensor. There is no tab and I've tried putting in the battery multiple times. The light flashes blue once and then nothing. I've tried removing the device and then scanning the QR code and adding it but I'm still getting the same error telling me to pull the tab on the back of the sensor (which still doesn't work).  Ring Contact Sensor - this says it requires a factory reset. I've done all the steps (holding down the tamper button and reinserting the battery multiple times), the sensor light flashes blue once but then nothing happens on the app and it says it still needs a factory reset. I want to try removing the device from the app but when I tried that I got a "device out of network" error message.  I'm really at my wit's end - I tried calling Ring help on the phone but got an error message every time I put in my account verification number. If I hadn't just bought two new Ring cameras I would probably abandon the whole thing but here we are!