Good morning everyone! I had the same experience of you, I joined the trial period, I considered it not interesting for me and I immediately canceled.
I received an email from them with the cancellation ok.
After months I get a message that I would have to pay the annual subscription anyway.
I replied by saying that I had canceled, but they say I still have to pay anyway.
Since Usenet.nl is based in San Marino, I then contacted the CSdL - Confederazione Sammarinese del Lavoro (http://www.csdl.sm/sportello-consumatori/ - Tel. (+378) 0549 ******* Fax (+378) 0549 *******) who put me in touch with their lawyer, to whom I explained everything and gave him the evidence.
The lawyer filed a complaint in my name against Usenet.nl, intending to suspend any payment request against me.
After a few days I received an email from Usenet.nl telling me the final closure of the contract.
Since then I have not received any payment requests.
I advise you to do as I do, the more you will be and the Usenet will stop using these methods.
Greetings to all