Neighbour complain on noisy children

Hi there, I need your advice. I am currently 7 months pregnant married with a 2 sons, 4 years and 2 years old. Due to this Covid our BTO will be delayed till 2nd quarter of 2022, actual date was August 2021. We are currently living in a HDB with my family, our neighbours downstairs had come upstairs 2 time, 1st was in August and 2nd was early this month. He complain that the kids was running and bouncing, my parents house is a maisonette so our neighbour bedroom will be under our living room. My children are both in Childcare, they are only at home during the morning and will be back at home in the evening, and on Saturday and Sunday. The neighbour came and told us to stop our kids from jumping and bouncing, I am a bit depressed as they doing the minimal activity jumping and running. I have put carpet and mattresses, and after 8 pm on weekdays I will put them to sleep. But as usual the kids when walking, they would do some movements and maybe the neighbour will find it disturbing. I need your advice, on whether there is any soundproof mat for me to purchase and any other ways to minimise the movement of the children walking. Thank you. 🥲