I need to identify to mammilaries

I have to mammilaries that are very similar but I'm not sure about the species nor if the two of them are the same species, i do realize the first one has curlier "hair" but i was told they both where Mammillaria hernandezii, it's just that seeing photos on the web they seem a bit different from Mammillaria hernandezii

The first thing to say is that neither are M. hernandezii.
The second plant is M. duwei, which is now lumped into M. nana. The first needs a lot more light, but I think is M. bocasana.

thank you ver much, it seems I was lied to when I got my plant, the M. duwei still a beatifull plant, only lied about the name.