Well here is to give you some light on the subject:
probably the problems is that your company is charging you rooming charges since verizon cellular are not working anymore in Puerto Rico the company sold all their actives a few years back now is call "claro" an independent company from Latin american no relation to Verizon anymore.
there are a few celular companies in the island that probably works as a local service in Puerto Rico:
most of those companies also work on st.Thomas for example I have at&t and I can call Puerto Rico with no charge since it's considered local.
PROBLEM: from other islands you are in rooming charges if you call Puerto Rico
so maybe is best you call your comapany before taking a cruise so you know those "hidden charges" they don't tell you about it
I hope this help...