You can contact Squarespace Support via email or live chat (during operating hours) here: https://support.squarespace.com/hc/en-us/requests/new
Fill out the topic and subtopic, then scroll past the suggested guides and you'll see the links for email and live chat.
All support options and hours are detailed here: https://support.squarespace.com/hc/en-us/articles/219648707