Phishing??? Or what?? 57976 no

You voluntarily joined that? Or someone else used your number?

Subscription service, you will be billed again next month, if you don't cancel it.

Look at the site for a method to cancel?

If done by accident or some adware click, you maybe be able to get your network provider to cancel and refund?

Not really categorized as 'Phishing'!

Phishing is the fraudulent attempt to obtain sensitive information such as usernames, passwords and credit card details by disguising oneself as a trustworthy entity in an electronic communication.[1][2] Typically carried out by email spoofing[3] or instant messaging,[4] it often directs users to enter personal information at a fake website which matches the look and feel of the legitimate site.[5]