BRUSSELS (Reuters) – Belgium’s labor authority launched the first stage of a court case against British food delivery group Deliveroo on Monday, challenging working conditions for the firm’s 3,500 riders in Brussels.

The authority, a division of Belgium’s Ministry of Labour, filed the case over the legal status of Deliveroo’s riders after an 18-month investigation concluded the company is failing to respect Belgian labor law.

Riders are paid per delivery and considered self-employed, meaning they have no access to healthcare, overtime pay or holidays.

Deliveroo said a court decision that riders were employees rather than self-employed would deprive them of the flexibility many wanted.

The case was scheduled after the hearing to go to trial in October next year, and could last several years if there are appeals.