As salaamu alai kumm wa rahmatullahi wa barakath,
The following image best describes the plight of the effort of tabligh and the people involved in it.
So just ignore the doubting thomases and keep doing the effort for whatever we say, whatever we do, people will always have something to say.
Note: Not comparing the work to a donkey, its only an analogy.
Image courtesy: NA.
Wa alai kumm as salaam wa rahmatullahi wa barakath.