Poor service and product inferior

Purchased a 10L Andris Lux Over Basin from Plumblink in Randfontein 0n 14 March 2022.After plumber that was refeered by Plumblink installed the unit it was not sufficiently heating up enough water enabling me to wash dishes I lodged a complain to Heat tech in Pretoria.Subcontractor came out same day and reset thermostat to no avail.Lodge another complaint and contractor came out inthe last week of March.After numerous calls I was informed that they need to replace element on unit.As they did not have an element said they will be back,they returned on Tuesday the 5th of March.Replaced element on geyser and unit warms up about 3 liter of water after which water is cold.I told contractor from Heat tech that I was not satisfied at all.Wrote an e- mail to Heat tech.Got an answer from Bianca saying that if the thermostat was reset and new element installed that was it.She also imp**** that unit should not be installed under pressure.I asked for an explanation as this is not mentioned in assembly and operation instructions.Up to time of this review no feedback from Heat tech.There is a pressure valve in the inlet to the office as there should be.I explained that in another e- mail to *** feedback as yet.I bought a product that is brand new and is suppose to do what is claimed on their advertising of this Geyser.They now try and soothes this problem by ignoring me.I would only be happy if they replace their faulty unit or refund me so that I can buy a new Geyser from somebody else.I did not pay for a unit that was repaired twice.Their customer service is not very impressive and shows an attitude of not caring whether the customer is satisfied or not at all.