"this person has delated her/his questionnaire by herself/himself" ?
It means that he/she has DELETED the questionnaire or profile.

Most of the time I usually see that " this person has deleted her profile."
I don't see any sense in only deleting the questionnaire.

Sometimes the profile is deleted by the manager.

So , this in my opinion is not blocking a person.
When you block a person he/she cannot send you a letter or a wink.

And he/she cannot look at your profile and pictures.

To do "light blocking" you can put your profiles settings so , that only people who are in your favourite list can write to you and read your profile.

But that means that some people can not contact you .....

I hope that you understand this a little ?