Analyse competiror sells on an online platform

On a daily basis, I analyse a competitor's e-commerce by looking at the changes on his online product stock. I make this manually (with Ctrl+C and Ctrl+V with a MS excel spreadsheet that I created) by putting all his items on cart and reaching the maximum quantity allowed for each item. So then I have the entire product stock on a daily basis. By analysing the changes, I start to know how much sells my competitor does daily. So then I want a program to do this and generates me a report. For more detalis, get in contact. Regards, Gary Dunnel