First and foremost, we cannot cancel your subscription. Paypal controls the rebilling and YOU (that's right!) control the subscription. Only you can cancel it!

To cancel, if you really must, just go to paypal.com.
Log into PayPal
Click "History"
Select "Subscriptions" from the "Show:" drop-down box.
You may need to select a longer timeframe from the "For:" drop-down box if you have had your account longer than a month. Try selecting "Past Year".
Press submit.
You should see an entry called "Subscription Creation" with "MSX" in the "Name/Email" column. There will be a link in the "Status" column that tells you the status of the subscription. If it says "Active", click it.

Click the button that says "Cancel Subscription" and follow the remainder of the steps.