Nuisance email

Questions:

I am getting a lot of unsolicited e-mails, is there anything I can do to stop them?
I have seen a website condoning/encouraging violence against certain groups of people, what should I do?
My friend/ex partner/ex employee is sending me threatening/nuisance e-mails/texts/phone calls, what can I do?
Where can I report a suspicious / phishing / scam email?

I have got my bank statement this morning and there are some transactions on it that I have not made, what should I do?