New Tub Problem- won't get clean!

I've had a brand new Veritek tub installed about 3 months ago in a complete bathroom remodel. From the beginning parts of the tub have been very hard to clean. By hard to clean , i mean it takes 30 to 45 minutes to clean parts of the tub floor and it never looks completely clean

The general contractor says that this is normal... I simply can't believe this is true. There's only two of us using the tub! I specifically bought a fiberglass tub because I've read that fiberglass tubs are easy to clean. He says there is nothing wrong with the tub even though one can see a 6 by 6 inch area that never gets clean and seems to have scratches or something (the area feels different than the rest of the tub). I suspect that either something was spilled or dropped on the top .

Can someone give me opinion on whether this is normal? The GC seems to think if I'm not satisfied that it could be refinished (at my expense!), but it's a new tub. Of course we tile around the tub!

thanks much

I'm stressed!

This has been my experience and I'm not very happy about it myself. I bought the Kholer Villager expecting it to be much better at the over $300 price tag. I was wrong.

Tom