you would have received a 5498-SA for contributions. the 1099-SA would only be issued if there were distributions. if you have issues talk to the employer - they should be able to tell you who the trustee is and how to contact them
A 1099-SA is only issued if you make withdrawals from an HSA. The W-2 indicates your employer made deposits. Your W-2 indicates that your employer deposited $2500 in an HSA on your behalf, either free money or your money from a salary reduction agreement taken from your paychecks. If you did not make deposits into an HSA, you need to get a corrected W-2 from your employer. The IRS has this information and if you don't correct it or report it, they will start sending you letters and assessing extra tax and penalties.