How on earth after spending so much money and i am unable to disable unwanted notifications and can’t get rid of it

If you are referring to SMS then please contact your Carrier.

You may also see the options here --> Block, filter, and report messages on iPhone - Apple Support

There are many third-party apps in the App Store that claim to do exactly what you are looking for.

agreed... this is a scam in itself and these ‘time saving devices’ are actually causing stress rather than easing the lives of people.

so... I get links to websites and in other forums on here about this suggested going to the third party, which I thought were the email addresses linked to the calendar. I have three a Hotmail a Gmail and iCloud. The invitations were all on Outlook calendar, according to my iPhone calendar. (You can see this by hiding all calendars then adding each calendar individually to see which one is the problem.)

So I go to Outlook and there are no entries at all in that particular calendar.

dont decline or answer any of the invitations because it only confirms you exist to the phishing/spammer bot.

there is no option to delete even though the so-called help on here says just whack it junk... if there was that option we wouldn’t be here???