Error in RTI reporting

Hi, I am an employer and we have made an error on our payroll system where an employee is shown on our system to have been paid £800 when she wasn't paid £800. She in fact received no pay for the period W28. I've reversed the pay on our system and issued a new P45 with the correct figures. I contacted our Iris Payroll helpline to ensure I was able to inform IR of the error and was informed by them that I'm not able to do that this year, I would have to send a EYFPS next year to rectify the error. The staff member in question no longer works for us but the £800 is still showing on her UC record due to RTI information and is therefore not receiving any UC due to this. I have tried contacting HMRC Employer helpline who say they cant do anything, our payroll software company say they can't do anything. My question is how do i tell HMRC that this RTI information was an error, effectively she needs to have the £800 deleted from her records and this can't wait until next year and needs to be done straight away but according to the experts this can't be undone by any subsequent RTI submiossion from the employer until the next financial year. The ex member of staff has contacted HMRC and UC hereself and is being told they can't do anything until I rectify this and i'm being told I can't do anything.

Hi mark Virgo,
All payroll products support sending an amended FPS as standard.
Therefore, if your software does not currently allow an FPS for the relevant tax year, you should approach your payroll software provider to establish when they intend to make the change to their product.
In the meantime the emplolyee should contact the Personal Tax helpline on 0300 200 3300 to discuss further or the UC department.
You could give a letter to the employee explaining the situation and they could provide this to the UC department to take into consideration.  
Thank you