Is there any other way you can get proof of payment?
If you remember who you paid service charges to, contact them to see if they will issue a letter or statement confirming that you paid that amount.
For your health expenses, if you have health insurance, your insurance provider might have evidence of your expenses and again issue a letter to that effect. If you don't, then ask your GP to issue a statement showing how much you paid them and do the same with your pharmacy.
Expect to repay the tax on any item that you can't prove you paid.