BT Landline

I have a 12-month BT landline contract - that is prepaid - with 9 months left. I also have from BT a free calls package and unlimited broadband. The broadband is slow - never reaches 2Mb download - but I think very expensive compared to BT deals for NEW customers and that after 12 years waiting the prospect of fibre is no nearer. The Broadband + Calls package is around £28 per month.
I appreciate that moving to a new broadband provider will not increase my speed but hopefully it would reduce the cost.
As far as I can see my problem in switching the provider is the 9-months (around £90) prepaid line rental to BT. Is my only option to wait for thsi to expire and then switch provider?
I would be grateful for any advice?

Plusnet would allow you to keep your BT land line. I think your would have to pay a bit more.

On the download speed side, what are the attenuation, connection speed and noise margin figures from the modem?

Hello, I don't see any issue using another provider for the last months at BT who, unfortunately, you do have to remain with - to get full use of your prepayment. Sadly, there's nothing devious about them not giving a refund, as they tell you that clearly at the beginning. Having said that, it's still a rip-off - with no justification that I can see!