That is somewhat odd. When you say you refurbished, presumably you bought fixtures and fittings? Did you not get a receipt for any of these items?
How much of the €15,000 relates to labour?
Off the top of my head this is what I paid in cash:
3.5k wooden floor supply (the supplier came to the house with samples)
1k wooden floor fitted
800 electrician
2k supply and fit of carpets (again came out to the house with samples so no retail premises)
200 plumber
1k plasterer
2k painter
500 waste removal
400 gardeners
1k kitchen fitter