Royal Bank of Scotland (RBS) and its National Westminster Bank (NatWest) division have been fined £2.8m for poor responses to customer complaints.Financial regulator the FSA said the bank responded inadequately to more than half the complaints it reviewed.Some 53% showed deficient complaint handling; 62% showed a failure to comply with FSA requirements on timeliness and disclosure of Ombudsman referral rights; and 31% failed to demonstrate fair outcomes for consumers, the regulator added."We expect firms to treat customers fairly and that consumers can be confident that their complaints will be dealt with properly. The failure of these two high street banks to deal adequately with complaints put consumers at unacceptable risk and the fine of £2.8m reflects this," Margaret Cole, the FSA's managing director of enforcement and financial crime said."The poor complaints procedure of RBS and NatWest came to light during our review of complaint handling in major banks. The review showed that banks need to make major changes to handle consumer complaints fairly and the FSA will continue to take appropriate action to ensure these changes are put in place," she added.RBS co-operated fully with the FSA inquiry, meaning the fine was 30% less than it could have been.