Webroot and trojan

[Arab Nights (imported)]

Over a year ago I posted how I had gotten Webroot from BestBuy and it seemed pretty good. I have gotten complacent thinking it was the wall to end all walls. Note that I did not dump Malwarebytes Anti-malware from my computer. I would update it and run it periodically just for grins. and just got the first trojan horse on it while Webroot was silent. A couple of points.

It, of course, makes sense that it is best to have multiple backups. (The problem I ran in to years ago is that is you have multiple it is like taking multiple medicinies, one can interfer with another). Any others that people would suggest? At what cost and where do you download it?

If I had to guess, I would guess that it came from an email yesterday that raised red flags with me. It was from "Dropbox" to "multiple receipients" with cc to me. Since in my work I do get large documents from dropbox, I was curious. I opened it but not the attachment on my iPhone to reply requesting the sender to ID themselves. Since then I cannot access new emails on my iPhone and got the trojan horse on my laptop. I need to call Sprint tech support. Does this make sense? Is there anything else I need to do?