That's correct, there were close to 150 stamps, that why I said you still met the rules even though you included so many damaged stamps. There were about 105 undamaged stamps (many of them low value common definitives from the 1970s to 1990s period).
I have four regular exchange partners from Spain, three of whom I have swapped stamps with for more than 15 years. None have ever had any issues sourcing stamps to put on their envelopes. Perhaps they get them from their post office, or perhaps they order them online from correos.es (with delivery in 3 days and shipping free if you order for more than €20)? But they are clearly available for purchase.
And I don't think a creased Nigerian envelope (it was folded because it didn't fit into your envelope to me) with common stamps from the 1980s is an adequate substitute for a current envelope from Spain - but that may be a matter of opinion, even though I don't think any cover collector would put such a creased envelope into their collection.
Anyway, since this was the second such letter I received from you I have now (sadly) blocked you ... the first person I have ever blocked.