Broadband install (England) not honoured - can I take legal action

So I'm with Talktalk in the UK (South East England) and currently on their ADSL fibre plan. We've just received FTTP availability in our area, so I signed up hastily for that.

I've organised it via Talktalk's live chat (because phones aren't a thing anymore). All well and happy, terms were clarified pretty well to me, outlining how much we're paying per month, install dates, what to expect, necessary visits in the house and inspections to know how they can install the fibre and ONT and whatnot into the property. I was given an install date - 11th September, and was clarified that a) there may be visits before the date by Openreach to assess the property and b) the date given may not be the date when the line will go live. I was also told to expect a welcome pack, including 2 new routers.

I work in IT and I myself provide FTTP upgraded to customers (businesses even), so I know how the whole process works. Before the install date, we sort the equipment i.e. routers, configure them, and post it to the customer before the install date. And if anything goes wrong or causes delays i.e. Openreach needs to obtain landlord permission, need to do extra digwork for the fibre line, then we have to let the customer know.

I booked the upgrade 2 weeks prior, and did NOT receive any correspondence from Talktalk at all. I left it until the install date, in case it will arrive on that day.

Install date comes by, I booked a day off work, no routers arrived, no engineers arrived. Waste of annual leave.

I even contacted Talktalk live chat at 4PM on the day, and I was told that the engineer is floating about; they're just doing other work, and that they should arrive by 6PM.

6PM passed by, nothing happened. No visit at all.

I then went back to Talktalk to complain, their first response was an apology, and they offered to rebook, but they "will get back to me when they find out when they can offer me a new date". They also apologised about the routers - they were actually not organised when I booked the upgrade, but they will be shipping them straight away.

I tried another "expert" and I tried to threaten that I will leave for another provider. They offered for me to stay, and they'll give me a £100 voucher of my choice. To choose between Tesco, Amazon and a Prepaid Mastercard voucher. I chose Amazon, and confirmed that they will email it to me in a few minutes. Again, nothing arrived.

So I went back to chat the following day and asked about the voucher not being sent. I was then told that they will only give me the voucher once the new line is up. I shrugged it off as I was working, but I asked for another affirmation that the upgrade will still go ahead.

Their response: "There was a system glitch. You will have to rebook the upgrade"

Obviously, I was fuming. Asked them why do I have to rebook, and not them. I again threatened to leave, and the response I got was "Sorry to hear that. Let us know when you decide to cancel your package." and ended chat. Funnily enough, after that, the Talktalk routers arrived!

Next day, I rebooked it, to give them another chance. Booked 2 weeks ago, with an agreed date of 1st October. Same thing - contracts sorted, dates agreed, what to expect, same as last time. I asked about the routers I've just received and was told that they will send a prepaid bag so I have to send it back. Fair enough, maybe it's tied to the line, but it kinda feels like a waste. Especially when I saw the bags have WEEE on them - they're just going to get disposed :(

Fast forward to today, same thing as before, NO correspondence, I have to contact them everytime to ask for an update and all I'm getting is "We can assure you your line will go live on 1/10/24."

And just now, I'm on the live chat with them, to hear the same crap as before, with a new tidbit - my welcome pack will arrive once the line is live.

Also for the record, we have not been charged for the upgrade. We're still paying for the current, slower package.

Any advice would be appreciated.