Go back to them and explain you are not getting on with them.
It may be the frame is not adjusted properly and that effects your visibilty thru the lens.
Depending on the type of progressive lenses used by them, it may be possible to change to another type more suited to your requirements.
State clearly what specific requirements you have in relation to your job.
Don't let them fob you off with excuses and if not happy, ask for the Dispensing Optician, not just a salesperson.
After all " not fit for purpose may come in to the equation"