Unfamiliar transactions on your statement happen for a number of reasons. Here are some of the most common possibilities. If none of these seem to be the reason for the transaction you're questioning‚ we'll look into it for you.
Many service providers' terms and conditions allow them to automatically collect subscription charges if you don't cancel within the specified time limit (e.g. 3 month trial period). Be sure to read the service provider's contract regarding their cancellation policies.
If you have cancelled the service, be sure to ask for a cancellation number.