WELSH language campaigners picketed Aberystwyth Post Office at the weekend, with students leading the demonstration over its lack of Welsh services.
The action was the second picket outside branch in north Wales.
Customers had been incorrectly told that Welsh is not an official language and others were directed to nearby post offices to get services in Welsh.
But the Post Office told Welsh language campaign group Cymdeithas yr Iaith that it would tackle such problems and prevent similar incidents
However, campaigners say that more customers have faced anti-Welsh attitudes — despite the promises to put things right.
Campaigner Jac Jolly said: “The Post Office is not willing to accept that we have rights to use the Welsh language.
“The staff told us that the Post Office had said they would have to pay for Welsh lessons themselves and learn in their own time: that's not good enough."
Cymdeithas yr Iaith’s Jeff Smith said: “It is crucial in terms of the rights of Welsh speakers in Aberystwyth — and for the Welsh language in general — that people can live their lives through the Welsh language.
“But in this post office, the rights of Welsh speakers are being eroded and the rights of staff are being ignored.
“Not only is there a lack of Welsh language services but customers are being treated badly when trying to get a service in Welsh,” Mr Smith said.
A previous picket was held in October due to several complaints over the attitude of the Post Office towards the language.