SAO PAULO (Reuters) – A group of bondholders that are Oi SA’s (OIBR4.SA) largest creditors demanded on Sunday that the company’s top executives meet them as soon as possible to renegotiate a debt plan.

In a letter viewed by Reuters that was addressed to top Oi executives and board members, Oi’s two biggest bondholder groups demanded the carrier’s executives meet in New York to “negotiate in good faith and on an expedited basis the terms of an acceptable plan(s) of reorganization.”

The letter was sent by the main advisors of the International Bondholders Committee the Ad Hoc Group of Oi Bondholders.

An emailed request for comment from Oi was not immediately returned Sunday night.

The Oi restructuring, which started in June 2016 and remains Latin America’s largest bankruptcy protection case to date, has been marked by a series of disputes between creditors and shareholders.

On Friday, the steering committees of the bondholder groups and the so-called ECAs rejected Oi’s recovery plan presented on Wednesday.

They said the company “seems to have spent time negotiating with a small group of conflicted creditors, some or all of whom also hold equity, for a failed deal that focuses exclusively on preserving value for the existing shareholders.”

Oi’s revised restructuring plan proposed by management and approved by the carrier’s board “ignores fundamental creditor concerns, threatens long-term viability of company and abusively enriches existing shareholders,” said the statement.