New agency and payslip looks wrong

Jonny17291:
Bit off topic but wasn’t sure who else to ask that might know the answer.

Newly qualified driver (7 month’s), I done 6 months work of agency to start myself off and all was fine, I did my hours and got taxed fine and I had a holiday pot which I gradually grew up with the hours I worked and after 6 months I got a lump sum as I left that agency.

Now my question is I’m in a temp to perm job for 12 weeks through a agency and after 12 weeks I will get offered a job if all goes is well. The way it works is the company tells the agency how many hours I’ve worked and the agency tells an accountant firm to pay me. It’s fine through umbrella (1st for me). I done a lot of hours this week 68 ish and was hoping to get a large pay slip £964.08 but I took home £641.21 so a difference of £322.87, which I thought was very high so I asked for a breakdown. The reason I got was this.
Good Afternoon Jonathan,

I hope your well.

Please see below the breakdown of your wages:

Based on £9.66 per hour for 39 hours, £19.32 for 8.75 hours, £14.49 for 21 hours and £114.00 expenses in total.

Total £964.08. (before any deductions).

Deductions from the Reconciliation Statement -

Company Overhead – £10.00
Employers’ NIC - £82.95

Deductions from the Pay Advice -

Tax (PAYE) – £92.60
Employee’s NI - £55.78

Holiday Pay - £69.79 – this has been accrued for you so it will appear as a deduction.

Total Deductions – £322.87

Total deductions [£241.33] – Total gross figure [£964.08] = [£ 641.21 ]

What I don’t understand is my holiday pay is being deducted from the wages I’ve earned, surely you earn holiday for the hours you work not the opposite, It feels its just a way for them to earn interest on my holiday pot but it’s not even a holiday pot as it’s my wages… So basically it’s a 0 hour contract is what I see.

If anyone can make sense of this I’d highly appreciate it. Thanks in advance

Could be wrong but surely you shouldn’t be paying the Employers Ni contribution - that’s there job■■?