Dates for all of this?
"Note that as per Crystal Web's terms of use, a cancellation may not be processed if an outstanding balance remains on your account due to Crystal Web for any services from any date. Same-month cancellations must be submitted before the 19th of each month. "
http://support.crystalweb.co.za/hc/en-us/articles/203383272-How-do-I-cancel-my-account-
VDSL and ADSL have the same set-up, the only difference for VDSL is that your router must be VDSL capable.
I don't believe you when you say support had no clue what VDSL was, I think there is something missing there.
As above Orihalcon's comment, but what package did you sign up for?
Would love to listen to those call logs/have the Crystal Web rep comment, I'm sure there is more to this.
EDIT:
The only difference is the username/password combination as provided in your welcome mail, the same as all other ISP do it.