Lood die Loodgieter [Pty] Ltd AWFUL!

We had team come and fix a leaking pipe in our home. Thereafter zero correspondence. My husband booked them and I dealt with them on the ground. Neither of us got an invoice, or a statement, and we never got a courtesy phone call. 89 days letter a debt agency sends an email notice with a final demand which blew me away as the amount owed is now double. I had not received any correspondence from them in any way shape or form up until that point, 89 days later. Upon probing we discovered that the Lood die Loodgieter misspelled our surname in the email address, their response to our email was 'the email didn't bounce', so they claim to just keep sending notices and demands to an incorrect email assuming we are getting them. We didn't receive any texts or messages from Malan, Pauley and Partners either, upon reviewing the email demand we discovered incorrect details there also. How am I suppose to make a payment if I don't know the cost involved or the banking details. Their managing director enquired via email as to why I had not contacted them either... well I suppose life happens, weeks go by and no thought is given, I am not employed by them so why do I need to their work? The moment the invoice did appear this morning from the MD herself it was paid on the spot, as work was done and pipe is no longer leaking. I refuse though to accept the fees due to the debt agency. I can't pay for Lood die Loodgieters lack of administration savvy, or customer care.