I got a similar response to a complaint earlier this year. Ironically the complaint was because of Avios not posting (in the region of 60,000 - so obvs an amount worth spending time getting!). They seriously thought that 5,000 Avios was acceptable compensation for not getting 60,000 Avios.
To be fair, a call to CS reopened it and it was resolved (and I did receive both the 60,000 and 5,000 Avios). Five months late, but I got them!