I've had this company pay for a survey or two pretty much instantly, but when it comes to offers for using apps or signing up for things, I've never been credited.

I have sent an email near daily since 30th July, to which I have had no response bar the initial automated reply asking for details that don't make sense - SubID & PubID?

They won't get back to you, they clearly don't check the support requests. Avoid.