to get broadband with BT you need a phone line so maybe you don't use it but you do have a line with a number try connecting a phone with a filter and dial 17070 option 2 see what number you get and also if there is any noise best done with a corded phone if you don't have a phone then a cheap phone can be bought for about £5
this investment could save you the callout fee of £129.99 should you get engineer visit and fault on your side of test socket