Just out of interest where did you go for your varifocals? The only reason I'm asking is because I know of many and I mean many people who have had problems with their varifocals that were purchased from a certain large chain of opticians.
However, I had to keep going back for the same reason as yours. It turned out that the ultra thin lens that I had chosen for my varifocals was actually the problem. I had them remade with a normal thickness lens and I've had no more problems. Same happened with my work colleague. As soon as the lens was changed to normal thickness he had no further problems.
As far as your question goes, I really don't know the answer, however, I would try to exhaust the different options with the original opticians first. Then, if still not satisfied, you could go to another opticians. However, if there does not seem to be a problem with the eye test you will no-doubt have to pay again (for the eye test).
Let us know how you go on. Varifocals are so expensive so it's worth pursuing - I wouldn't go for anything else now!!