My Employer has not paid me on my correct pay day and also not given me a correct pay slip representing the hours Iv worked and money I should have earned. What do I need to do regards to UC and ensuring I still get paid correctly and so I can still received my reimbursed childcare costs?

So I have recently returned from long term sick and have been on SSP. I have now been back to work for a few weeks and should have received my pay from them on 01/12/2025 for any hours worked between 03/11/2025-30/11/2025. In short my team manager didn’t report to payroll that I had returned to work and worked shifts so payroll put though my payslip as earning nothing (ssp had just come to an end). I have since been speaking with management and they say they have corrected everything from their side but now payroll are adamant that they won’t give me an emergency payment to correct this and are now leaving me with nothing until the next scheduled pay run on 29/12/2025. Firstly, I’m annoyed that due to a company error I have been left without any pay but also secondly my payslip is factually incorrect and therefor reporting to hmrc and inturn UC are incorrect too as my payslip does not show what I should have been paid and what Iv worked etc. I am now worried that my UC payment will be effected and as it looks like I now haven’t worked during this UC assessment period (despite that I have but just haven’t been paid for it) that I now won’t get reimbursed my childcare fees. Also I’m not happy and concerned that by payroll saying they will add in the owed hours to my next payday that this will also make it look like Iv earned more this next months assessment period than what I have worked and should be accurately paid for.

I don’t know where to start on how I report this or even try to explain especially over my UC journal. My manager has personally said he will put something in writing to say I have worked as he knows it’s his personal mess up but it’s still not a corrected pay slip nor have I been correctly paid. I have already complained and escalated this within my employment for illegally withholding wages but they’re not interested and just told me to seek legal advice if I wish too. Actually shocking behaviour from them.

They have no care for the domino effect stuff like this will have on me financially through UC and how it affects payments. Totally inhumane behaviour from them.

Will I still get my childcare reimbursed for a single month of no earnings reported? I believe I was told there is usually a grace period of a month in which stuff still gets paid say if you were to leave a job and before starting another but is it the same in this case?