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.

 

If you have a choice of getting another job where you don’t have to deliver such items, you should go for it. Otherwise, you may take the job for Shari`ah allows for concessions or relaxation of rules in regards to matters that are unavoidable.

 

There is a juristic principle known as umum al-balwa which is invoked by jurists to consider it as permissible.

 

Furthermore, Allah reminds us in the Qur’an that Allah does not place on us burdens we have no strength to bear.

 

In light of these, I would advise you to continue the job – unless you find another job wholly free of all taints of haram.

 

However, if you continue, you should do well to purify the income from the taint of haram associated with it through istighfaar and extra charities.

 

Allah Almighty knows best.