To be fair, I believe you when you say it's not a Ponzi, in that I don't think you have the intention of paying back your early "investors" at all. I think it's an outright scam and that you will just make off with any coins you are sent. 5% weekly return works out to over 1200% per annum; 7% weekly return works out to over 3300% per annum. There is absolutely zero chance this is true, therefore you are a scammer.