Disgusting customer service

I bought a mommy and baby scale on the 4th February at Toys R Us Tokai as I have a premature baby and was told by my pedestrian to weigh baby before and after feeds. Within doing that I purchased a scale at Toys R us Tokai and then to find out that the scale was giving me the incorrect weight. Took it back today to do an exchange and was told that there was nothing wrong with the scale by the manager who firstly had no name tag and who addressed the situation with no sympathy and disrespect towards me and my newborn. As far as I know exchange period is within 30days providing you have the original receipt and packaging. Manger and staff was highly unprofessional as I was told to fetch my premature baby out of the car so he could see that the scale was giving the incorrect weight after arguing for almost 30mins. I then weighed myself and then baby and it clearly showed the wrong weigh in and was told that my pedestrian scale was incorrect which should be the most accurate out of all the scales. For him to have exposed my newborn to the mall that may have so many germs just for me to prove to him that the scale was in fact faulty is totally unacceptable! In my defence, customer service should be displayed, handled in the utmost respect towards the customer and there should be no issues especially a company like Toys R Us for newly mothers and infants. This issue could have been addressed efficiently and with a smile to make the process smooth and to make the client feel at ease. It's sad that Toys R Us has lost a valued customer.