A businessman convicted of harassing a manager of Danske Bank has said he intends to appeal the ruling.
Ivan Preston sent more than 400 emails to the bank and accused it of corruption.
The messages were initially sent on a weekly basis but eventually reached a frequency of up to nine a day.
They were also copied to other banks, political representatives and several journalists, including staff at the Belfast Telegraph.
Mr Preston (54), of Bryanburn Road in Bangor, sent the messages after a tender for work his courier business had made to the bank was turned down.
A judge at Ards Magistrates Court imposed a restraining order restricting Mr Preston from communicating with Elwyn Thompson, an official at Danske Bank, and gave him a conditional discharge for two years.
Speaking yesterday, Mr Preston said he would be launching an appeal and vowed to continue raising concerns about what he said was "sharp practice" within the banking industry.
"I now have a conviction for harassment but I haven't harassed anyone," he told the Belfast Telegraph.
"What I have done is try to shine a light and ask questions which are awkward for some people to answer. I'm just an ordinary person who has tried to take on the system, but the system has tried to silence me."
Mr Preston said he intended to appeal his conviction, and vowed not to be deterred by the ruling.
"My persistent efforts in having the truth exposed have met with various activities designed to prevent that from happening."
Mr Preston denied harassing Elwyn Thompson, a relationships and IT manager at Danske Bank's Donegall Square branch.
He admitted sending Mr Thompson, who deals with third-party supplier contracts, 357 emails between June 2012 and June 2013 after his tender was refused.
Many of the emails were copied to senior officials from other banks, including former RBS chief executive Stephen Hester.
A defence lawyer argued Mr Preston's long series of emails amounted to a sustained inquiry and was not harassment.
But Mr Thompson told the court the emails accused Danske Bank, and the three other large banks in the city, of having an "unfair bias against his successful business", and claimed the tendering processes were "corrupted".
He said Mr Preston began to question his personal integrity in the emails.
The court also heard Mr Preston attended the Danske brand relaunch media event, and was involved in a "brief confrontation" with chief executive Gerry Mallon.
After Mr Preston said Danske Bank had "links to criminal behaviour", District Judge Mark Hamill told him: "Do not mistake this court for a platform for your opinions on the banking industry. I do not have time to listen to your rants against the banks."
Example of Ivan Preston's emails: sent to Elwyn Thompson and 54 other recipients on May 23, 2013: "I find it a little bewildering that sports organisations i.e. the IRFU, the NI Football League, various sporting competitions, leagues and clubs are sponsored by banks.
The 'position' regarding sport, with the level playing field and fairness principles sporting organisations seem to go to great lengths to imply, and the connection via sponsorship by entities from what surely must be regarded as one of the most corrupt sectors, is perhaps indicative of how truly f****d up things, or society, are."