If you follow this link, you can cancel any paypal subscription. Note that a subscription is an agreement between you and Paypal – hence I cannot cancel a subscription for you!
You cannot reactivate your paypal subscription. In case you cancel your subscription you can however still manually prolong/renew your account here for a number of years you specify: http://openmtbmap.org/support/membership/
So follow this link, login to your paypal account, login, and you will see a list of all subscriptions you have, and cancel the ones you like (note following this link is the same as logging into your account and then go to "My Preapproved Payments" from within your paypal account):