HHow O start the spa event whenever I go there in Saturday for weekend it's always renovating
The Spa for M&S progresses with their levels.
1 Spa event in level 1 (M&S weekend at home)
1 Spa event in level 2 (M&S weekend at home)
and so on...
Once you've unlocked it via the first weekend event, it's accessible during the week (except Monday) through the train station.
The ladies inside the Spa are always available and not bound to M&S progression.
In case you're already in a higher level and missed out on the weekend events - you have to replay from level 1, or you unlock the gallery via cheats, so you can replay the events in there without the need to replay everything.