Wa `alaykum as-salamu wa rahmatullahi wa barakatuh.
In the Name of Allah, Most Gracious, Most Merciful.
All praise and thanks are due to Allah, and peace and blessings be upon His Messenger.
In this fatwa:
You are not required to pay any ransom as the farewell tawaf is only recommendable in Hajj and `Umrah.
Responding to your question, Dr. `Abdul-Fattah Edris, Professor of Usul Al-Fiqh, at Al-Azhar University, states:
There is nothing wrong in the case of the questioner, as the arrival tawaf (tawaf al-qudum) as well as the farewell tawaf (tawaf al-wada`) are considered Sunnah (recommendable); they represent a greeting to the Ka`bah.
Therefore, if a Muslim forgets or leaves out one of them either in Hajj or `Umrah, he or she does not have to pay any ransom (fidyah), as leaving a sunnah does not necessitate any ransom.
Allah Almighty knows best.