SpecSavers trying to destroy my eyesight.......

A few weeks ago I went for an eye test at SpecSavers N1 City.I then waited a few weeks for my glasses.When they arrived(2 pairs),I could not see out of either pair.I then went back to SpecSavers with both pairs and explained to them my situation.They were not very accomadating and took the one pair back and told me they would send to the lab for adjustment.A couple of days later the pair arrived.I then went to try them on,it was still not ok and I could still not see out of them.Now I had two pairs of glasses and each with different strength lenses.They told me that it must be like this and my eyes will adjust to the lenses.I was not convinced.I have not worn them as I can't see out of them.I then went for a SECOND Opinion at another Optometrist whom then did another eye test.He then tested the two pairs from SpecSavers and told me that the pairs obtained from SpecSavers were too strong for me and that's the reason I cannot see out of them.I am wanting to return these two pairs to SpecSavers for a refund as they are no good and cannot be used.I would also like SpecSavers N1 City to take full responsibility for their error in the supply of both pairs with different strengths not suitable for me.....