Secure invoice doesnt work AT ALL

I would NOT recommend the plugin nor Payone. We are trying for 2 weeks now to get the secure invoice gateway working, but it just doesnt work anymore. I dont now. It always ends with an error message “preauthorization (rec)” and on the frontend “Payment guarantee has been rejected [351] / Keine Bonit?t” even when ordering for 40€. 30 people have tried and all have been rejected. We even called Payone 4 times and the only response we got was “it should be working, it is all looking good, try it later”

So much money we have lost already…