Cash under the table?

OVer seven hundred for work on two main drains for cleaning out, and after two requests , waiting months in between for my bill of sale reciepts, I have nothing. Do these people not understand Landlords need receipts, and bill of sale for taxes?. Are they trying to stash money under the table and not report it to Revenue Canada, by not issuing bills of sale on purpose?. Obviously I am done with these pricks.