Need help with a calculation

I'm no good at Maths so half of the categories I do not understand, so I hope this is the correct place. I only got a C at GCSE stander in Maths, and that was about 2/3 years ago lol.

Anyway, I was wondering if someone could tell me how to figure this out, below I have put figures showing a total number which is spilt into 3.

Payment 1: £909.15

Payment 2: £909.15

Payment 3: £936.70

Total Amount: 2755.00

Well basically the "Total Amount" SHOULD be "£3385", so how would I work out Payment 1, 2 and 3? As to me it does not look like it is simply 3385 / 2.

Thank, in advance :)