Upset customer

When my husband needed to go for an operation we caled bankmed and they have given us 100% cover to say everything will be paid at bankmed. Now we getting statements from the Dr's and hospital claiming that medical aid only said it was R18000 but that was never the case when we called in. I want to know what is happening and why should I be liable for a cost when I have medical aid for 100% cover. I would like for a manager to contact me as the staff will not give me the correct information I am looking for.