If-statement with NSMutableString hasprefix phone number (Beginner) - ios

Question

Hey I don't succeed to make a functional if-statement with my NSString
j is ABMultiValueGetCount(phones).
I've three cases : j=0, j=1, j=2...
I would like that when j = 0 or 1 or 2, that doesn't take number with prefix 02...
if j has number with prefix 06, save this number.
if j has number with other prefix save it, except if number with prefix 06 is already saved.
I tried to make this code, but it doesn't work, I don't know where is my error :
if (j == 0) {
if ([phoneNumber hasPrefix:#"02"]) {}
else
if ([phoneNumber hasPrefix:#"06"]) {
person.number = phoneNumber;
}
else
{
if ([phoneNumber length] == 0)
{
person.number = phoneNumber;
}
}
}
if (j == 1) {
if ([phoneNumber hasPrefix:#"02"]) {}
else
if ([phoneNumber hasPrefix:#"06"]) {
person.number = phoneNumber;
}
else
{
if ([phoneNumber length] == 0)
{
person.number = phoneNumber;
}
}
}
if (j == 2) {
if ([phoneNumber hasPrefix:#"02"]) {}
else
if ([phoneNumber hasPrefix:#"06"]) {
person.number = phoneNumber;
}
else
{
if ([phoneNumber length] == 0)
{
person.number = phoneNumber;
}
}
}

Answer 1

This seems to be the problem (it should be != instead):
if ([phoneNumber length] == 0)
To make the code simpler I would just do something like this - should be the same result:
if (j >= 0 && j < 3 && ![phoneNumber hasPrefix:#"02"] && (![person.number hasPrefix:#"06"] || [phoneNumber hasPrefix:#"06"])) {
person.number = phoneNumber;
}