Improving Cell Phone Signal

I purchased a Wilson WeBoost 470103 from Solid Signal. Could not see an improvement. Called Solid Signal, and they had me call Wilson. The Wilson tech had me set my iPhone to 4G, not LTE and to show db level, not bars. I had -95db. The lower the number the better. The tech said that to be effective that the signal needed to be -85db or less, smaller number. Also, stated that Solid Signal should have told me that when I ordered and to return it which I did. Because the unit would work with a good signal, Solid Signal charge me about $30 restocking charge even though the unit I purchased was the one recommended by them.