What is the point of a gap cover when they fail to cover the gaps and shortfalls in a medical aid

What is a point in having Gap cover when it does not cover the Gaps, the whole point of taking out gap cover was to assist in the shortfalls of my medical aid, now my claim is being rejected, because my medical aid did not have enough funds to cover the scan, is this not the definition of a gap? but no they see this as it being declined. how is it declined and why then is there gap cover. Is this not false advertising, in the name itself, they try to word it to state that they are not a medical aid, which is obvious, but they are not a GAPCOVER?????????? why then do we pay if they are not going to cover the gaps in the shortfalls of medical aid?????