A quick heads-up.
I've seen two screenshots now from different people that recently made contact with A. They both received the same canned e-mail (T address) with new, lower prices for the N. One of them contacted A to ask about the price changes. A's reply was that he has run out of D so for now at least, he's back to selling Pisa.
Pisa (the factory, the brand) went out of business a while ago. This is why A switched to D. Which must mean that the Pisa bottles are from an older batch. Pisa remains lethal for up to 4/5 years after production date so this is not necessarily a huge problem but keep it in mind if you decide to contact A. Ask him for the production date of the bottles.
Also, one bottle of D is enough for one person but one bottle of Pisa (100 ml) contains 6.3 grams of pentobarbital and that is pushing it for a (reasonably) healthy adult. Keep this in mind too.
I have no idea if D will return.