mac mini late 2012 wont boot after ram upgrade - 3 sets of ram tried

A simple ram upgrade on my mac mini turns into a nightmare going on for more than a month now..

Ram on my model is 4 GB 1600 MHz DDR3 and i want to upgrade to 2x4GB. I initially bought this one http://www.newegg.com/Product/Product.aspx?Item=N82E16820104230

which didnt work, it didnt boot at all. After a bit of research i figured the problem was that the memory was Cas Latency 9 and that the mini wont support it as its original RAM was CL11.

So i returned it, they checked it for any fault (found it ok) and replaced it with a CL11 one, this one in particular http://www.ramexperts.com/mushkin-977033a-ddr3-sodimm-2x4gb-8gb-pc3-12800-1600mh z-sodimm-apple-11-11-11-2-1-5v.html

With this one the mini would show me a kernel panic thing with a bunch of erro info on a black screen and then a message that the mac has a problem and it ll restart. Couldnt boot after several tries. I returned this ram too, the shop checked it and found it faulty so thet replaced it (after another wait of a couple weeks cos they didnt had it in stock..).

Today i received the **** memory and again i get the same kernel panic page and mac wont boot...

I swapped over the sticks, waited 10secs as adviced before fitting them but no luck..

So is this another faulty ram modules or i am ordering the wrong ram..? Its driving me crazy.

I researched and found that 1.35V or 1.5v wont matter as many people report success with ram at 1.5v with mac minis late 2012 model if thats an issue..

Any ideas before returning this ram once again..? I never thought upgrading the ram my mac would be such a tedious process..