(b) Any claimant who has a direct contractual relationship with any subcontractor of the prime contractor who gave such payment bond or other financial security but has no contractual relationship, express or implied, with such prime contractor may bring an action on the payment bond or other financial security only if he has given written notice to such contractor within ninety days from the date on which the claimant performed the last of the labor or furnished the last of the materials for which he claims payment, stating with substantial accuracy the amount claimed and the name of the person for whom the work was performed or to whom the material was furnished. Notice shall be served by registered or certified mail, postage prepaid, in an envelope addressed to such contractor at any place where his office is regularly maintained for the transaction of business or served in any manner in which legal process may be served in the manner now or hereafter provided by law for the service of a summons, except that such service need not be made by a public officer.