Hi. Resolving this issue on ZTE Maxx should be a relatively easy task as itsStock ROM must be largely available for download. Since it is necessary to reflash the device's ROM/firmware, let me confirm if the ZTE Maxx is of the same hardware as the ZTE Max (with one 'x')
Edit: :( the two do not prove to be identical. You will try and lookup any other numbers that may be of some help on the white sticker under the battery (apart from the two IMEI #s and ICASA compliancies). You will need to go via your retailer (the shop you purchased the phone from - eg. Pep Store), for assistance with a firmware/software reload as the firmware pack for this model not made publicly available by ZTE sadly. See http://www.satechhelp.co.za/8772/Privacy-Protection-Password-2100mhzimei-865730020094740