Client booked in, got charged but I haven’t received confirmation neither did they

Hi there,

I would like to ask for an advice or help with a booking issue. My client booked in a session through my website, acuity scheduling link. They got charged but never received confirmation email. I haven’t received confirmation email either and the time slot is still showing as available. 
Nothing like that ever happened before. Did I accidentally change some setting or is it issue of the client’s bank?

Any advice is appreciated!