Upgrade still not done after 14 days

I ordered a Fibre upgrade form L to XL on the 15th and was told this would be switched over within max 7 days. At the time of ordering (after a call from Tango offering an upgrade) I mentioned that, when I first ordered Fibre in my area, there was a restriction o the speed due to a technical upgrade that needed to be done. I mentioned that I would only upgrade if I actually really benefitted from the new speed) After this was not the case, I have contacted the company in the knowledge that I have 14 days to cancel. I was told a technician within 24 hours. This was not the case and I have received no call. I did contact support by email with the case number and again, apart from an automated acknowledgment, I have received no answer. I spend repeated long periods on the phone in the queue. This seems to always have 2 callers in front of me and stays like that for a minimum of 30 minutes with no change in number of customers before me.
I am running out of options and would hope this is solved promptly!!
Not particularly impressed.
CASE 766754