my call was disconnected when talking to a person regarding a change in our mobile account

my husband passed, called on 12/2 to change the our credit card,  I thought when I gave them the new # , this would be for all payments.  The call was for one payment.  My service was turned off.  I spoke to a fellow and changed the card.  He received the card # and was going to start my cell service.  I accidentally disconnecte our conversation.  I thought he would call back, but he did not.  What can I do to make sure there I didn't need to do or know something else.