Burt Barrett and Gene O'Neill of Northway Commercial Brokerage have completed the sale of 20 Cushing Ave. near the Plaistow, N.H. line. The 6,500 s/f structure was built in 2003 and was deemed surplus by Haverhill Bank after a recent acquisition. The Northern Massachusetts Telephone Workers' Credit Union purchased the branch building for $1.5 million and intend on opening a branch in June. Both Barrett and O'Neill represented the seller and secured the buyer.