Something weird occurred in our Musjid. On Friday, before the khutbah, a qawwaal was allowed to sing naa'ts.

Answer

The miserable, evil qawwaal who sang the haraam naa'ts should have been expelled from the Musjid. Singing for public entertainment is haraam. The haraam is aggravated by the pollution of the Musjid in this haraam manner. In fact, the haraam singing has now been made part of the Jumuah ibaadat. May Allah Ta'ala save us from these scoundrel qawwaals and the scoundrel trustees and the scoundrel imam who allowed the evil singer to perform his haraam singing.