"datepicker is not a function" make conflict with Shailan Dropdown Plugin

Hi,
As my Dropdown menu plugin (Shailan) is not working anymore (sublevels not showing), I look in Firebug and found an error coming from Custom Contact Form:

TypeError: $m(".ccf-datepicker").datepicker is not a function
	$m(".ccf-datepicker").datepicker();

From line 4 in “https://chileanchamber.be/wp-content/plugins/custom-contact-forms/js/custom-contact-forms-datepicker.js?ver=3.4.1”

When CCF is enabled, Shailan Dropdown is stuck, when CCF is disabled Shailan Dropdown works fine.

Do you have any tips to clue the problem ?

Thanks alot ??

https://www.ads-software.com/extend/plugins/custom-contact-forms/