Feed URL showing 404

I started my podcast feed using SSP about 3 weeks ago. For the first 2 weeks it was working fine and iTunes and other services were autoupdating when I released an episode.

I noticed that recently my episodes weren’t updating. It turns out my feed was returning a 404 error.

The feed which SSP settings tells me to use is https://themedicalcollaborative.org/feed/podcast (this returns a 404).

I’ve found the correct feed to be at https://themedicalcollaborative.org/index.php/feed/podcast
I don’t know why this changed, it was not something I did myself.
I had the feed URL changed at iTunes and Stitcher, however now other podcast providers (like PlayerFM and Pocket Cast) aren’t picking up my new episodes.

My questions are:
1. How can I get the feed URL back to what it was before?
2. How can I ensure other podcast services pick up my new feed (or if i can switch to my old one, even better)

Cheers!