HMRC paid me and now asks for the money back

[sophia.ft]

Good afternoon,

I have just received a p800 from HMRC asking me to repay a sum of money that was paid to me last year and I am confused about it.
I indeed received a £1236 cheque in Sept. 2016 as HMRC said I have paid too much tax on year 2015-2016.
I have cashed the cheque, and now in April 2017 the P800 says that I owe them the same amount.
When I rang them, they said that when they issued the cheque, they didn't have the information of my previous job (I have been employed by company A until October 2015 and started with company B the same month).
What I don't understand is that my tax code is correct, and also the P60 I received in June 2016 was showing the correct information from both my jobs.
I don't understand how HMRC now says that they did not have information that I had another job and only knew about job B until early 2017 if the P60 was correct back in April 2016.
I can understand that the first company did not inform HMRC on time, but they would have because I gave my P45 when I started my job and have always paid the correct amount of tax. Now this £1236 needs to be paid back according to HMRC.
Could you please advise on what is the best course of action I should be taking, just repaying this amount or try to speak to them?
thanks all

[AmanSood]

Hi Sophia

Difficult to address what the next steps should be and it all depends on whether you want minimum hassle and want to just settle the amount. Alternatively, if the amount HMRC is asking for is not immaterial in your view, I would suggest getting a tax advisor to review the position and confirm whether this amount is actually due. You would of course have to weigh up the cost of this vs simply settling the amount.

Thanks

Aman