That is not normal. I've never seen this. If she has made a payment and it settled, then I would go to the transaction, get its paument details and get the lightning invoice (there's usually a "pre-image" but it seems their wallet doesn't provide that???!)

Then try to get support from them here: https://support.walletofsatoshi.com/support/home

You are both fortunate that you both used the same service provider and unfortunate that you both used a custodial wallet.

My guess is that the payment system worked flawlessly but there was some issue at the service provider level.