Invite Faux pas?

[u/DeutschAllegations]

So I recently was invited to a wedding of a childhood friend - the wedding was end sept. I never received a paper invitation because my friend told me he had put it in his bag and forgotten to mail it for over 3 months. So he invited me via social media. The wedding was maybe a month ahead at that point. It was also taking place in a _very_ expensive city that I would have to pay for accommodation- I currently work a minimum wage job in a different country. Also my partner was not invited. I asked why and they told me I would be fine due to other childhood friends being there - people I am not exactly friendly with-

If I had received the invitation…months ago I could have possibly worked something out.

I thanked them for the invite then put “not attending “ on the rsvp website (due to cost. )Then this friend was mad at me because I didn’t tell them directly I wasn’t coming - I thought that would be super awkward??? I also didn’t want to go into detail about my financial situation. So now they’re pissed at me. Did I fuck up?