Paye details entered wrong by employer

Hi. My wife’s payroll clerk has entered her pay duplicate times for each month ie. twice in august for example. This has happened on numerous occasions and she has now got an estimated income of over 18 k but is likely to only earn 10k. Hmrc have sent a letter claiming that her tax needs paying and are taking it back through wages. Effectively I need to know who has to rectify this issue and what we can do as the payroll clerk an accountant I’m registered is not responding to any calls or emails and is refusing to rectify the issue. Thanks

Hi,
Your wife's employer will need to rectify this and send the relevant amendments through their payroll software.
Your wife should discuss any underpayment with Personal Tax on 0300 200 3300. 
Thank you.