It's the rDNS of the last person who used your IP. Just let your provider know you want it updated to your own - having the wrong rDNS sometimes may affect email delivery. Changing the rDNS will not interfere or screw up your email.
Your VPS provider should have given you access to a control panel. You should be able to change the rDNS from the control panel, and if this doesn't work for whatever reason - open a ticket and ask your provider to change the rDNS for you.
The owner of your IP address, in most cases your provider, needs to update the PTR record. A simple ticket will do the job, and if it doesn't, I'd advise on searching for a new host
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