Can I claim VAT back

we are a small company that resells software, we recently filed our second years VAT return, my question is on some of our transactions we only made 15% but we get charged 20% vat by our suppliers so we are actually losing 5% on these deals, we paid in the region of £25K and that is what we collected, i have read a few times that vat can be claimed back but how do I go about this, looking at our online hmrc is looks like like we are not due a refund. we do not have an accountant. so it will be left to me to figure it out.

any help is greatly appreciated…

If you are on standard vat scheme you can reclaim vat on your expenditures, if on flat rate then generally No.
On standard say you charge vat to your customers for 35
and your expenditure vat amount is 25, you can off set it and pay HMRC the balance 10.

If you have entered figures correctly on QF it should work out vat due accordingly