Any opticians about? Varifocal question

[sergeantmajor]

DH got new varifocal specs 4 weeks ago. He can't see with them, everything is out of focus, near and far, and strains his eyes. The optician says that the prescription is correct and he will get used to them. But after 4 weeks it's still no good. The lenses cost £500 and I'm not sure he can get his money back.
Does it take that long to get accustomed to them? What are our chances of a refund given that lenses are made bespoke?

I had Varifocals a month ago from Boots. They told me I had a month to change my mind.
Immediately my left eye felt like it was being pulled and made me feel sick. They adjusted the glasses and that was better, but I still could not cope not being able to read without moving my head.
They let me changed to single vision lenses and gave me a refund for the difference in cost.