To contact the Secured Sable ONE Credit Card reconsideration line, call 1-833-583-8383. The Sable Credit Card reconsideration line is a way for denied applicants to request a second review of their application and potentially get the denial overturned. In the case of Sable Credit Card, the reconsideration line is the same as the general Sable customer service number.
If you call to request reconsideration from Sable, make sure you are prepared to make an argument for why you should be approved. You will typically only have a shot at overturning a denial if you can prove that your financial profile is better than it appeared on your initial application.
For example, if your credit score went up significantly or you got a raise since you applied, you could argue that you are now more creditworthy. Alternatively, if you were denied because of incomplete or incorrect information on the application, you could ask for reconsideration after fixing that error.
At the end of the day, you probably won't be successful in overturning your denial, but there's no harm in trying.