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I've got the same feelings. Wi-Fi signal is not very good on 1st floor...getting disconnected constantly and download speed is really bad. I'm new to Vodafone. I wonder if I can connect Wi-Fi extender via Ethernet cable and that will give me more reliable connection to my pc. When I'm on ground floor where the router is, experience is not as bad.
that's what I did, I got a pair of TPLink , but be aware that this solution has some minus, I have issues with those TPLink some disconnects (sporadic issue , as there are times without an iterrupt,) and I read a lot of people have this issue , not only with the TPLink btw, it depends of your home's cabling btw., but anyway it was the only solution to connect my PC on the net, as the rest of the family had no signal downstairs (mainly for the Roku on TV)
Vodafone now supply usrname and password on request, I got mine on chat last night, you just have to pick an authorised router from the list approved by openreach, you dont have to buy it, just mention it
I spent a fair bit of cash on an Asus DSL-AC88U it has loads of features and multiple wireless channels including a Guest one. I was ready to sign up untill Vodafone told me I could not use it. Told them it was a deal breaker, I don't know of any other provider that does not allow you to use your own I mean lets face it the freebies tend to be pretty crappy bits of kit. I will be signing up with someone else and if there is a mobile deal then Vodafone will be losing my mobile contract as well......
I asked for my login details via online chat and the advisor happily obliged.
I think you should try again... you may get lucky.