A warm welcome to the forums. What level of self diagnosis have you completed? See links below.
Broadband is not going to work well if the "phone" line is not working properly.
Please perform a quiet line test - dial 17070 select option 2 using a corded phone plugged into the test socket behind the face plate of the master socket. It should be silent. A noisy phone line (or no dial tone) will have a marked adverse impact on the performance of broadband.
If the line is noisy or there is no dial tone, then a PHONE LINE fault needs to be raised with your phone provider. If this is PlusNet, you can report a fault on line using the button below. From the Q&A list, choose the one which matches the problem, 'open' the 'section' and click the trouble-shooter link. NB: If you receive a failure message (rather than a log-in prompt) then log-in to the user portal in a different browser tab and attempt to use the trouble-shooter again.