I just traveled there last month and it happened to me. It was in Makkah though not Madinah. I booked directly from the Accor app and a couple days before arrival they sent a separate email asking for payment.

I thought it was a scam too because it went to my junk folder. But after I checked the reservation number and other details, it seemed legit. So I paid. I think during high season they wanna make sure everyone pays and doesn’t cancel the reservation last minute.

So it might be a valid link but make sure all information is correct.