Frustration

After Sata hard drive I was very happy for my 2.5 "with an adapter Digitus, I ordered a second hard drive to the new adapter Digitus though I unfortunately had to make the following experiences.:
1. Why a USB-Y cable when a power supply is needed anyway?
2. There are 2 connectors for power supply, 3 or 4 poles; both for SATA, which is the right one? Manual does not help.
3. The pins of the connector are bent partially and push yourself during mating to the rear.
4. When using the 4-pin connector attached hard disk presented immediately feed your function !!! You will not run once more.
5. When testing with an old hard drive that but still ran the same result: a total loss
When measuring arose at the output of the power supply 5 respectively. 12 V, so okay; the error must therefore lie / reverse polarity in the plug adapter)?;
The part was of course back immediately on the defective hard drive but I remain seated; I have my doubts as to whether this is an original Digitus product.