Forgot Passcode on Sonim Flip-phone. Factory reset instructions?

Sonim is wanting me to provide a proof of purchase in order to recieve technical assistance, which I am currently unable to locate. Has anyone had to reset one of these before? Not worried about losing data, just want to be able to use the phone again.

crwdns2893858:0crwdne2893858:0 crwdns2893862:0crwdne2893862:0


crwdns2889612:0crwdne2889612:0 0