Bad Business Practices

In December & January I requested the services of this company as we had issues with the plumbing. They fixed that drainage issue successfully with minimal hassle. On 2019-05-14 I sent out an email to multiple companies asking those companies to provide me with quotes as one of our other pipes was overflowing with sewage - I requested quotes as I saw on multiple plumbers websites that you can get discount from alternate plumbers if you provide a written quote from another plumber. The only reason I did not do the same in December was that the drain blocked up on the 24-12-2018 and this plumber advertised were open 24/7 and when I called they advised that they could assist even though it was in the December vacation time and most other plumbers were closed. I did not include any other means of contact except by email and it is my belief that they were not even included on the mail as I did not have an email address for their company - thus how they were aware that we had plumbing issues again (different drain) I will never know. That same day (2019-05-14), we managed to unblock the drain and plumbing services were no longer needed as the drain was blocked with a combination of leaves (there is a tree which sheds a lot of leaves near the drain) and hair (as this is the drain from the bathroom) and some strong chemicals broke down the blockage. On 2019-05-22 these plumbers showed up while I was at work and my niece and nephew (underage and awaiting our return from work after they finished school) let them in thinking that we forgot to let them know that the plumbers were coming (the minors were aware of the drain that was blocked the previous week and were puzzled as they were aware that this was unblocked). As we were still at work they attempted to unblock the drain (I say attempted as it was already unblocked) - they stated that there was a rusted pliers blocking the drain even though this was not affecting the drainage at all as the chemicals mentioned above took care of the problem and there were no longer any issues with the drainage within or outside the house making the a pliers being in the drain redundent. They also tried to charge R350.00 for an unneeded service which we never requested in the first place (why should I pay them to unblock a drain when the drain was not blocked). When I asked for proof of me asking them to provide a quote or proof of acceptance of quote, they sent me an image of when I texted to request the repair of the previous plumbing issues in Dec 2018. They could provide no evidence of me accepting a quote or even communicating with them in May 2019 whatsoever (even though they stated that I phoned them the morning of 2019-05-22 - this was not possible as I was in meetings for most of the day with 45 other people and they also had no proof of said call), however, I have clear evidence that I did not communicate with their company since the previous plumbing issue in January was resolved. They also threatened to black list me (verbal threat) and blacken my name (as they stated in their WhatsApp message to me "I will use you as an example") when I refused (upon my return home) to pay for a service I did not request or accept a quote for as the drain was no longer blocked in the first place. It is my belief that were trying to take advantage of me and my family. Needless to say, I will never be doing business with this company again.