Your wife went to Africa without taking her residency card, therefore, she cannot get back into the country. This is because she cannot prove residency. The rules on this are very clear and apply to everyone. Your MP cannot change the rules. See an immigration lawyer for re-application advice.
Perhaps you should consider visiting the immigration offices and talking to someone there about your problem. If you can't visit them, try contacting them using the contacts on www.uscis.gov/portal/site/uscis, and talk to an immigration attorney for legal advice.