I would like to know if I have to pay twice

[lola1]

One of my tooths in the left front of mouth has broken maybe because the nerve of the tooth was removed 20 years ago. The dentist told me that I have the choice between a crown or a plate but he told me that maybe he will not be able to insert the crown or it can break and in this case I will need a plate. He told me also that if he cannot insert the crown I will have to pay again for a plate. I have paid for the crown. I would like to know if my dentist cannot insert the crown if it is accurate that I will have to pay again for the plate. I heard that if a further treatment is necessary after two months of a course of treatment has ended we will not have to pay again