You don't say what phone you are using.
Some phones have a call blocker built in (save the number then try opening the contact in your phone's call settings and touch the three little dots and see if it gives you the option to block).
Alternatively you can download an app. I downloaded a free app from the Play Store called "Calls Blacklist" for my android device.(There are others but I find this simple and effective).
As for Premium Texts. Blocking them won't prevent you being charged. You need to unsubscribe.
Try texting back "STOP" or "STOP ALL" to the short number used to provide the service.
If you want to say thanks > click 'Kudos'.Answered your question? > click 'Mark as Helpful Answer' also.