At the time when we were making OPAS aware of the problems many people wrote to OPAS and reported that by messages. Nowadays the only reason for writing OPAS would be with a complaint that might not be covered by the complaints already known to OPAS. (Or to get a copy of the Mike Cawley complaint.) Letters from OPAS or the Ombudsman's office are also here.
[515] Ombudsman Office letter to Oliver Letwin.
[287] Another identical reply from OPAS
[275] Letters to/from OPAS, complaint largely subsumed by Mike Cawley's complaint.
[261] Another identical reply from OPAS
[260] Letters to/from OPAS, complaint subsumed by Mike Cawley's complaint.
[229] Letter to OPAS suggesting cross-subsidy is "morally wrong and not permitted within the legislation"
[208] Letter to OPAS and Mark Oaten
[185] Letter to OPAS from retiree.
[126] Another retiree who wrote to OPAS
[114] Another person writing to OPAS
[093] Reaction to OPAS letter
[089] Best not to use email for OPAS
[087] Reporting writing to OPAS
[084] Another person writing to OPAS.
[083] Bullet points for writing to OPAS
[051] An email sent to OPAS
[037] Another person writing to OPAS
[031] Another person completing Form of Authority for OPAS.
[017] Actions taken by somebody, including OPAS interaction.