sorry im still confused. How am i supposed to plug a molex into a sata powered riser. I could use an adapter but i think that causes more problems...
A quality adapter should not cause problems in general. However, in the highly unlikely event that your specific risers require use of the 3.3V line, a 4-pin molex to SATA adapter would not suit your needs.
Personally, I would not return the risers. However, I would limit use to 1 power connection per line of connectors off of the PSU. (Perhaps you could do two, but one is ideal.)
Molex connectors tend to go over-spec better than SATA (perhaps due to their geometry), plus the original specifications already rank SATA with lower max current (and thus power) capabilities than 4-pin molex. However, SATA power can *usually* do the job, if you distribute the load properly (which may be difficult if you have only one PSU).