PROVIDENCE, R.I. - Ward 15 City Councilwoman Sabina Matos, who is accusing her opponent, Oscar Vargas, of not living in the ward, filed a letter with the Board of Canvassers on Friday presenting new evidence that casts doubt on Vargas’ residency claims.Vargas, who is running as a Democrat to represent Ward 15, testified before the Board of Canvassers at a hearing Tuesday that he lives in a single-family home at 150 Dora St.