Taxi drivers in Ottawa say they are losing money every day to unlicensed and unregulated Uber drivers.

Now, they say, the value of their retirement investment is also in jeopardy.

Moni Assi, is helping his retired father to sell his taxi plates. Those plates have dropped in value significantly since the arrival of Uber.

“It costs, considerably less than it did a few years ago,” says Assi. “A few years ago it could have sold for $300,000, now maybe for $250,000 or $260,000.”

The Union, says taxi plates used to sell in a few days by word-of-mouth.

Several drivers have been trying to sell their plates on Kijiji for many months.

On Thursday, two uber drivers will be challenging the City of Ottawa in court. They are contesting their $615 fines for providing a taxi service without a license.

Uber said it would not comment on a matter that is before the courts, but in a statement said: "Costly enforcement operations, that seeks to protect an industry that has remained unchanged for decades only hurts the consumers that have been asking for expanded transportation choices."

It is estimated that Uber is worth about $40-billion, and it has a reputation of not backing-down from legal challenges in cities worldwide.