Android : Get contact phone number by ID - empty Cursor

So I'm having trouble getting the phone number of a contact using its id.

This is the code I'm using to retrieve the number:

public String getNumber(){
        //gets numbers by id
        if (hasPhoneNumber){

            ContentResolver contentResolver=context.getContentResolver();
            Cursor cursor=contentResolver.query(
                    ContactsContract.Contacts.CONTENT_URI,
                    null,
                    ContactsContract.Contacts._ID+" = "+id,
                    null,
                    null
            ); //TODO : resolve empty cursor error
            //contact seems to have no data available?

            if (cursor.moveToFirst()){

                cursor.moveToNext();

                String contactId=cursor.getString(cursor.getColumnIndex(ContactsContract.Contacts._ID));

                Cursor phones=contentResolver.query(
                        ContactsContract.CommonDataKinds.Phone.CONTENT_URI,
                        null,
                        ContactsContract.CommonDataKinds.Phone.CONTACT_ID+" = "+contactId,
                        null,
                        null);

                if (phones.moveToFirst()){
                    while (phones.moveToNext()) {
                        this.number=phones.getString(phones.getColumnIndex(ContactsContract.CommonDataKinds.Phone.NUMBER));
                    }
                }

                phones.close();
            } else {
                test("cursor error...");
            }

            cursor.close();

            return number;
        } else {
            return null;
        }
    }

It works with a few contacts but most show the "cursor error..." Toast (test("cursor error...") )

It's always the

Cursor cursor

that has the error.

My guess is it's empty but I know I have those contacts phone numbers saved. How do I fix this? Are there other values I have to request?

Thanks in advance!