One of the problem with this code is here :
name += contactName[];
This instruction won't insert anything in the array. Instead it will concatenate the current value of the variable name with the string representation of the contactName array.
Instead use this:
contactName[index] = name;
this instruction will store the variable name in the contactName array at the index index
.
The second problem you have is that you don't have the variable index
.
What you can do is a loop with 12 iterations to fill all your arrays. (and index
will be your iteration variable)