Reinstate *******

My wife changed jobs where she came off medical aid and was told it can be reinstated with in 3 months with no penalties, she did all the calling/following up sending paperwork back and forth etc etc...... finally close to the 3 month period she received the confirmation letter saying the account is reinstated... Luckily she phoned to confirm what her debit would be end of January...... To her surprise and shell shocked we are been told to pay R16000.00 apparently it is for the months we weren't covered? Our question is why not reinstate as of January? That was the request in the 1st place its **************** to pay for something we were never covered for. Is this normal practice i don't see this detail in the contract???