I finally decided to quit clicking on some of the following PTCs recently because of non-payment and poor customer service. I don't say these are really scam PTCs but I am not happy anymore with their service.
DailyClicks - it has paid me before so i bought a premium membership and referral package but when i reached about $53 earnings, they stopped paying and they are nowhere to be found. I cannot waste my time clicking on their ads even if they got tons of them, without getting paid. There is also no way of contacting them.
DailyClicksPro - same owner as DailyClicks where I sent my sentiments abut DailyClicks but i got no response from them either Scam or not, i guess it is leaning to being a scam site too! I hope i am wrong, though.
CashLinkz - i paid $55 for a premium membership and never got my status changed. I sent them trouble ticket but has never heard from them since May 18th. I claimed a refund with paypal and don't know what's gonna happen next.
Paidvg - I paid $59 for a premium membership and referral package but didn't get it. The owner tried his best to refund all the money he owed the members but i was not lucky enough to get mine as he didn't have enough to pay everybody.
clix4coins - just disappeared ...... i also have premium membership there and bought referral package
I guess i still have lots to add here later but that's it for now. PTCs are very risky to do but i have left a few in my list that have been here but who knows one day, these just disappear too. Most of these disappear and send a message to members that they are just upgrading their server or whatever! Then after days and days of waiting, your money is gone......
I only invested on those i know that have paid their members with proof of payment but i guess even with these proof, you cannot be guaranteed they stay long so if you take the risk on doing PTCs, go for those that have established a name already. Do not invest on those that just launched or so that may give you tons of ads to click but won't last. But either way, everything is a risk!