Terrible Spa customer service.

I bought a voucher for a three hour Spa treatment. On the voucher it states they are open Mon- Fri, Sat, Sun and public holidays. The voucher is valid until 31 August 2019. When phoning them for a Sunday booking, Zizi (she refused to give me her surname), refused to make a booking for me on a weekend as they are fully booked until the end of August, stating that I HAVE to take 3 hours off from work to do the treatment during the week. Keeping in mind that I live an hour away, so I have to take 5 hours off of work. She was terribly rude, worst customer service I have received in a very long time. False adverti*****t, and now I have to battle on my own to get the refund as the Spa is not liable. Do not book at this Spa, unless you have ample hours available during the week.