Hey, guys. I just finished talking to my first real "nightmare" client that is completely ignorant of SEO and the work that I did for him. He is now threatening to call Paypal to dispute everything he paid me. I was hired as a pay by month for SEO with no contract, because he was a friend of a friend so we just did it between us. I worked for a few months and then had to stop for health reasons. I pretty much gave him the last month for free because I missed about a week of work and didn't want to charge him. It's been about 3 months since he paid me for SEO because I told him I was dropping him. Out of no where he texts me some crap like "i dont believe you did anything good while I hired you so give me all of my money back or Im calling Paypal". This guy didn't pay me with a paypal account, he paid me by using a credit card via paypal Invoices that I sent him. It's been about 3 months since the last paid invoice. What can I do to assure that this douche isn't successful at getting the money that I rightfully earned back or causing problems with my account?