What's the problem?
I would give this ago, its amazing stuff to have around the house, https://www.youtube.com/watch?v=pJnaLmR7oyg
Try Williams waterless Car Cleaner
I use the bathroom magic eraser.
I clean professionally and I always use a soap scum remover such as scrubbing bubbles or lysol power bath. Spray it on, let sit for several minutes, rinse. This is an alkali cleaner that breaks down the soap and mineral residue without damaging the surface
Gel Gloss! It's sold at Home Depot and on Amazon. After cleaning the tub/shower with it, give it a good buffing/polish w/a dry cloth and it will make it look brand new!