I would like to hire an Auditor

I had solar panels installed. The installer/seller were one in the same company they had me apply for a home improvement loan. I qualified for a 40,000 loan. I asked for receipts and never recieved them. Appliances were purchased, again no receipts which i need for my DWP refund and tax returns. I have supposedly money left over but the seller/installer is refusing to comply. So I would like shake up things by having them produce receipts for all materials, and work paid.