Check for existing email and mobile accounts

Imports from niche.com need to check for existing email and mobile accounts as they are not billable.

Add calls to:
- $MailChimp->call("/lists/member-info"
- $MobileCommons->profile
Hm a couple things:

1. It seems like `$this->existingStatus` would need to be initialized as an array() before you're able to assign the `email` and `mobile` properties, no?
2. If you're returning `$existingStatus` I think it should be `$this->existingStatus`.
3. What I think could make more sense is if you took `$existingStatus` in as a param, modified it within this method as you do, and then returned the modified array:
```
private function checkExistingAccount($data, $existingStatus) {
  ...
  return $existingStatus;
}
```