A former education organizer at the scandal-scarred activist group ACORN fraudulently used Department of Education phone-bill accounts to cash in on more than $500,000 in lavish Verizon customer rewards, city investigators charged yesterday. Donnett Davis, 31, of Brooklyn, allegedly obtained spa retreats, Yankees and Mets tickets, $5,000 IBM gift certificates and gobs of other garish goodies from Verizon by registering 9,000 DOE telephone billing codes under an ACORN account in her name, probers said. Usage on those lines between February 2004 and August 2008 was then counted toward her Verizon small-business rewards program, through which Davis was able to redeem...