Sirius, in regards to the hardware needed I recommend using an oxygen regulator with an adapter. Read this thread:
https://sanctioned-suicide.net/threads/max-dog-regulator-ridiculous-price.18831/
The comments posted by Fister will tell you the exact parts to get. You'll have to search on Google using the part numbers he gives but you'll find the needed items. There's a second thread linked to in the thread above you may also want to read.
Also for the tubing you need you can either buy oxygen tubing from Amazon or go to a local hardware store and buy a length of vinyl tubing cut to whatever length you want. I think the recommended length for this method is around 6 feet.
Incidentally, as you'll see on that thread, Fister killed himself this past weekend using the inert gas/bag method.
Eweforia I'm not sure what to tell you about dealing with the local company you contacted but here's what I recommend:
1) Go to a website called Cyberweld...(D O T)...c o m which has been recommended here on SS before. I can't link directly because of the new forum rule about posting sources.
2) In the search box type in: inert gas cylinder
3) This will bring up a list of inert gas tanks you can buy in various sizes as measured in cubic feet. 20 cubic feet is the minimum size you need for this method. You can also buy a 40- or 60-cubic foot tank that will obviously provide nitrogen for a longer period of time "just to be sure" if you'd like that. ONLY choose a tank listed as "inert gas". DO NOT get one marked "oxygen", "acetylene", etc.
4) Click on the size of tank you're interested in. On the product info page for each tank there's a dropdown menu under the word "options". Use the menu and select "Full Nitrogen". What this means is that Cyberweld will fill the tank for you with N2 then ship it directly to your house.
I hear you on black cats. I have two, a skinny little one who's very sweet and a big, fat, grumpy one.