I paid cash and now told I haven't paid

I had repairs done to my pool net - I paid the deposit EFT and I told them that I would pay the balance cash on delivery as per email. I handed the one installer cash - and they took the envelope and didn't ask me to sign the invoice that I had paid cash ( which I get told later - NOT before that it is company policy). I now get told that I haven't paid as the cash has now disappeared.<br> <br> They had to come back to replace one of the *****s and the lady at Aquanet said her installer said I would pay EFT on that day - but I wasn't even at the house - so didn't see them - isn't that a bit fishy!!!???<br> <br> Aquanet says that they have had their gentlemen working for them for years - I am not accusing anyone of *****ing - maybe the envelope got misplaced. I had the lady from Aquanet screaming at me on the phone like I was the ******** here - which is totally unacceptable. What I do know is I did pay the money over so it's gone missing from me to them.<br> <br> I am very upset about the way I was handled and spoken to - like I have crawled out of cheese. What I've learnt from this - don't pay cash!