(CNN) -- Chinese dissident artist Ai Weiwei lost his second and final appeal against tax evasion charges in a Beijing intermediate court Thursday, leaving him liable for back taxes and fines totaling RMB 15.52 million (US$ 2.4 million).
The court directly ruled on the case without holding a hearing and failed to serve Ai sufficient notice of the ruling, according to Liu Xiaoyuan, Ai's legal adviser, who accompanied the artist to court on Thursday.
"We submitted new evidence to the court after the first appeal," Liu said. "According to regulations, there should have been another hearing, but there was not."
"According to relevant laws and regulations, the court should send a formal written notification three days before the verdict," Liu added. "But the court just gave us a call last night telling us there would be a hearing today," he said, adding that no other members of Ai's legal team were able to make it to the court on such short notice.
"I'm more aware than ever now that I'm just as vulnerable as most other ordinary people in this country," Ai said, saying that he was "exhausted."
"We knew from the beginning that this was going to be a losing battle - to fight as individuals against the legal system," he said. "But to see so much arbitrary conduct in almost every step of their work is still very frustrating."
"We've been making a lot of effort getting our evidence, documenting our company's financial activities. And the court didn't really show any hard evidence today to convict us. They're openly violating the law by infringing on tax payers' basic rights and ignoring lawful requests time and time again."
Requests by CNN for comment from the court have not been returned.
Ai was barred from attending the court hearings held in June and July for his original lawsuit, with tens of police cars parked outside his home, studio, and the court. Liu said the artist was allowed to attend Thursday's hearing, likely because the case can no longer be appealed.
The 55-year-old provocateur has been battling the tax evasion charges brought by the Beijing tax bureau against his artistic company, Fake Cultural Development Ltd., for over a year.
The outspoken artist, blogger, filmmaker, and architect was on his way to Hong Kong in April 2011 when he was taken into custody at Beijing's international airport and detained for 81 days amid a government crackdown on political activists. Ai's studio in Beijing was raided, and his wife and several employees were taken into custody for questioning. The government campaign was attributed to fears of a potential Arab-Spring-style uprising, following online calls for a "Jasmine Revolution."
Seven weeks after Ai was taken into custody, state news agency Xinhua reported that Beijing police said his company evaded a "huge amount of taxes" and "intentionally destroyed accounting documents."
He was released on one year's probation the following June, with heavy restrictions imposed on his movements. Ai was forbidden to speak to the media or post on his Twitter account about his detainment. His phone was tapped, his e-mails were checked, and he had to report his appointments with other people to the police.
In November, the authorities demanded he pay the back taxes and fines within two weeks. Tens of thousands of supporters donated more than RMB 9 million (US$ 1 million) to help him, some even throwing RMB 100 notes folded into paper airplanes over the gate of his house. Ai used the donations to post a payment guarantee of the invoice in order to file a lawsuit to protest the charges.
Dayu Zhang, Tian Shao, and Vivian Kam contributed to this report.