I think you need to go to the closer vet, not the vet who did the ops, as he’s giving you bad advice. I would tell the other vet everything that has happened so far.
I know this must be hard for you, because the vet is telling you one thing, your mum is telling you one thing, and we’re all telling you another. It must be stressful. However, rabbits are classified as ‘exotic’ pets for a reason, and many vets simply don’t know how to treat them. Wick linked you to some reputable sites that back up what we’re saying though. Lots of us have had our bunnies spayed, and we’re talking with experience and the bunnies best interests at heart.
If she is given oral metacam, that won’t mess with her digestion, and it should be fine with the 24 hour shot too, but again, I would give the new vet the details of everything the previous vet did, including dosage of pain meds. If they gave you a printed reciept it should have that information on it.
It’s also very worrying that your vet decided to do a painful tooth trim during the spay, which might be another reason that they’re not eating (I saw this in your other thread, correct me if I’m wrong. Again, this is another reason that they need painkillers.
I’m glad that Cocoa is eating. She is probably eating enough to be ok, its a good sign that shes eating the mash on her own. Is she pooping?
It’s obvious that you’re worried and doing the best you can in challenging circumstances. Stay calm!