Advice needed re tax

[Mockingcurl]

I'm not sure if this is the right place for this.

I have just been sent a letter from The tax office saying that I have been overpaid, and I owe them £500. This is for the tax year 2011to 2012.
During this time I was employed by the county council, but on sick leave. I received full pay for 4 months and half pay for 6 months. I also received sick pay and then ESA Benefit.
The letter from the tax office says that 2 employers have claimed PAYE fit me. Hence the overpayment.
Does this mean anything to anyone? Any advice? All offers of help gratefully received.

Did you have 2 different employers between April 2011 and April 2012?

No. I was employed by the council, was on sick leave and claimed ESA as advised by HR. no idea what is going on.

In that case it might be a mistake - someone with a similar name to you or someone else's National Insurance number registered incorrectly as yours. You'll need to phone HMRC tomorrow and ask who this second employer is.

Brilliant. Thank you. I will look forward to speaking to them on a Monday morning.