Requires of a lapsed policy..where I'm told i don't even appear in your system

Good day... please assist me with regards of my policy... it's been years been with Zestlife cover where money has been debited in my account.. for the passed 3 months I've noticed they didn't debit anything and had tried contacting them but the number I used to call them with don't go through so I look for any proof at home I found a letter with the number that went through to cut it short they say they don't have any policy that have my name they ask me to send a proof I did yesterday today I recieved a email saying my policy has lapsed... when i tried calling them again with the number I got from email they say my name does not appear in the file.. even when I give them my policy number please help.