The actual TalkTalk support staff are only on this community during UK working hours, but there are a group of us known as 'Community Stars' who will try to help out whenever we are online. We are just customers like yourself, but we try to help where we can.
The support team will be able to run some tests on your connection to try to determine where the fault is (i.e. on the external phone line, or more likely to be in your property).
The chat Agents may have already asked you to try these things, but just in case they haven't .......
If your service comes down a phone line, and your master phone socket has a test socket inside it, then you could try the router in there (via a microfilter), that would then eliminate any of the phone wiring in your home as being a possible cause of the problem.
It would be worth going to the Service Centre to ‘run a connection test’ on your line, this will indicate if there is currently a fault affecting your service. You can also access this from the ‘My Account’ site.
If you have a landline phone can you check to see if that is working normally (i.e. you have a clear dial tone and no noise on the line).
