Please refer to the following two methods:

1. Order Tab
Go to [Order > Customers], select [Total Order], then customize [Order within] and click [search] to find customers with last orders within the customized date. You can retrieve the phone numbers after exporting list of those customers.




2. Customer Tab
Go to the Customer tab, expand [More criteria], then customize [Order within] under the order column. You can click [search] after confirming the date to find customers with last orders within the customized date. You can retrieve the phone numbers after exporting list of those customers.