There is a legal obligation for them to contact you 10 to 40 days before the end of your contract. That contact (by email in my case) included a number to ring. But in my case they contacted me exactly 80 days before the end of my contract (with offers that were not at all tempting !). Presumably they must contact me again (within the legal timeframe) and maybe the offers will be more tempting next time (but I wouldn't bet on it !).
Alternative ploy is to sign up to another provider and let TalkTalk contact you with a tempting offer. But make sure the other provider has an attractive offer, in case TT don't get back to you before the 14-day cooling-off period.
Also I have a note that I called 0345 172 0088 in October 2023 to negotiate my present 24 month deal (which I have been pretty pleased with), but what others are offering in August 2025 I'm not sure TT will match. Their initial offer was so unattractive that I sort of assumed they don't want customers in my area (an impression reinforced by the lack of TT offers on the comparison sites).
Since I wrote the above I signed up for a Vodafone FTTP service (I'm on FTTC with TT). This triggered an immediate email from TT which confirms the retentions 'phone number:
"If you've changed your mind or would like to chat through your options, just give us a call on 0345 172 0088".
And after experiencing the awful Vodafone "chatbot" there's still a chance that I'll call TT retentions !
