The phrase "again to complain" is correct and usable in written English.
It can be used when expressing a repeated action of voicing dissatisfaction or grievances.
Example: "After hearing the same issues raised multiple times, I felt it was necessary to speak up again to complain about the lack of progress."
Alternatives: "once more to express dissatisfaction" or "again to voice concerns".
But she says she would use Twitter again to complain.
After a few days in the hospital with IV's running she came home, right as rain, ready once again to complain about the food.
But after Forsyth told the TalkSport radio station that the nation should get a "sense of humour" about the incident yesterday, viewers rang in again to complain.
After what he called a night on the floor, Mr. Hirschfeld called the media again to complain that he had not been allowed to attend a news briefing at which Mr. Morgenthau announced his indictment and arrest.
This weekend, protesters took to the streets again to complain of the continued austerity and corruption that they said Mr. Rodríguez Saá had imposed on the country, forcing him to turn to unsympathetic leaders of his own party for support.
John Puzey Pontardawe, South Wales Your special report on the 70th anniversary of the blitz encourages me once again to complain about the lack of a national memorial to the 60,000-plus civilian dead of both world wars.
On the other hand, if sterling proves a weak currency relative to the euro, the French and Germans may once again start to complain about "competitive devaluation".
"Requesters... may be so frustrated that they become reluctant to use the act again or to complain to the information commissioner about refusals". The information commissioner's job is to promote the Freedom of Information Act and decide whether public bodies are entitled to keep requested information secret.
The Scot, 30, could again be heard to complain he was struggling with his movement, but once again his form improved as the match wore on.
I called my mother again, this time to complain.
Later that night, 57-year-old Galin again called police to complain.
