Teach Me ~"Email Hack"~

Hi for the past year i have been scamed about 50$ by my email included stuff such as my credit card.when i use my credit card they ask for my email, i put my email and the credit card number is always coming there. Some day a Dick ass comes and ask for my email so we could chat and i gave him my email emxaple@example.com then suddenly he reads all my mail and he has my e-mail account. so i was jsut wondering if anyone could teach me how to do that for educational purposes.Also how to prevent from it. I use Yahoo mail

Don't use yahoo mail. And don't respond to e-mail from nigeria. Solved.