The contact form should work - when did you send your message in? (I've moved your message to the Community sites forum - no need to do anything; just letting you know.)
Mary Cooch (personal account)
Mary Cooch (personal account)的帖子
Moodle in English -> Assignment -> File submissions default type. setting not working -> File submissions default type. setting not working
Why not try on the sandbox sites? (https://sandbox.moodledemo.net/) They no longer run 4.5 but you can see if it works or not on more up to date versions.