I hope you would not even consider abandoning a family member! If it was a kid, you wouldn't, would you?
Feliway is very good, used as directed. Nature's Miracle Just For Cats is an excellent enzymatic cleaner, used as directed. We use it and it works for us.
Calm, quiet, and serene are key words for cats. Samba is feeling insecure and needing to establish himself by marking. If there are cats outside in his "territory", you may want to cover windows where they frequent, so that Samba doesn't get stressed by them. This means closing blinds or it can mean putting up foil or other obstacle for awhile. Have you moved recently? Samba could be feeling insecure because he's "new in town" and he may just need time to feel more at home. I haven't visited the "spraying threads" here, but you probably will want to do so. A behaviorist may be helpful. There are ads for products and services relating to this issue on TCS's pages; one is http://www.catfaeries.com
and I've heard they are very good on this issue.
Don't give up and PLEASE DON'T ABANDON SAMBA -- he is a member of your family! Isn't he???