Somthing like this happened to me not that long ago. I bought an mp 40 for my tank to replace my small power-heads. I realized that this was way to much flow and I wanted to trade down. The mp40 had 1 day of running time. It was in perfect condition. I posted a trade for my mp40 for someone's mp10 and 50$. Within a week I got a reply, we worked out a deal and I shipped it to him and waited for my end of the deal. 2 weeks later still nothing, I gave him a call and my number was blocked. He deleted his email and I had no way of contacting him. I was 14 at the time. I'm 15 now. The only way I get money is from mowing grasses, cutting fire wood, and out door jobs. It took me months of hard work to save up for the power head and the guy knew that, I'm saving up for another pump right now. All I have on my 55 reef right now is a small korolla. Every thing in my tank is paid for by me and I take pride in earning my own money and supporting my tank. I've never done a trade other than locally since then.