Is there any mention in the Sunnah of what is known as "Al-Fidya" (the ransom), which involves reciting "La ilaha illallah" (There is no god but Allah) 7,000 times and offering prayers upon the Prophet after a person's death, and the implications of this, such as missing congregational prayers in the mosque?

What is mentioned as "Fidyah" has no basis in Islamic law; it is a misguided innovation (bid'ah dalalah), because acts of worship are based on divine injunction (tawqif), andخصص dedicating an act of worship to a specific time, form, and occasion not found in Islamic law makes it an additional innovation. Furthermore, the absence of those gathered from the congregational prayer at the mosque is a reprehensible act, due to the Prophet's (peace and blessings be upon him) saying: "Whoever hears the call [to prayer] and does not come, there is no prayer for him except for one with an excuse." Therefore, it is obligatory to warn against this innovation and clarify its danger.