That’s ridiculous.
Did you phone them to remind them the day before?
You could have refused it in the day of the service. They would have had to have found you a more suitable car, maybe from the Sales department.
Failing that you could have cancelled the service and said you’ll rebook it when they have a suitable loan car.
2024 - BMW i4 Grand Coupe eDrive 35 Sport
2020 - Volvo XC40 T4 Inscription
2017 - Audi Q3 TFSi Sport S-Tronic