I guess paying 15 bucks to find out whether something
is a scam instead of going on for months or years about
how it must be a scam
must sound very illogical if you suffer from obsessions.
The choice is not pay 15 bucks to a ponzi or complain about it being a ponzi for months. That is what is so illogical about your statement. If you want to buy hashing power from a cloud mining service, there are a range of options to choose from, most of which are ponzis and should just be ignored immediately.
See puppet's thread in order to learn the signs of a ponzi.
https://bitcointalk.org/index.php?topic=860400.msg9568209