Neighbour complained our reno caused his/her wall tiles to crack

As per title, neighbour recently complained to HDB that our reno work that was completed in January has caused his/her toilet wall tiles to crack. Complaints like this seem common from neighbours living below the reno unit, except this neighbour lives above us and also completed their reno just few months before us. Also we already moved in for close to half a year before this issue was raised. Any thoughts or advice would be appreciated.