Review of Wham Construction & Engineering Pte Ltd

I engaged Wham Construction and Engineering pte ltd to renovate my unit around january this year and experienced very bad experience. After renovation, I rented out the unit and things happened. Tenants complained blockage of pipe which caused the wayer flowed all over the kitchen, contacted the company in charge but no response. I had no choice but to engage a plumbed to clear the pipe which cost $450 and the cause of the blockage is due to cements, stones and debris which poured in by the renovation workers. After less than a month, worse things happened, tenants complained that toilet waste flowed all over the kitchen which caused tremendous inconvenience to the tenants who could not use both the kitchen and toilets. I informed the company in charge but to no avail. As it's an emergency, so I had no choice but to engage another plumber again which cost another $350, and he explained the cause as the previous plumber com contractor. I hoped to get a refund from the company by informing the person in charge but again there's no response. The picture below are stones sucked out from the pipe. I hope this review can let people who intend to do a renovation to be cautious in choosing a reliable and responsible company to do the job .