As a Networking company we used several different ISP's. Some that we have chosen, others that the client has chosen.
You will not find a worse ISP in the UK. Cheap? yes, no doubt, but you WILL pay elsewhere.
We had a chain of hotel clients that were under Daisy. Most had bonded lines; one with one ISP, the other with Daisy.
All the Daisy lines had faults. PRTG was off the wall constanly warning about down time.
Try and raise it with Daisy and you're wasting your time.
It's the router, it's the filter, it's the RJ11, it's the line.
Get the line checked, replace the router, etc...no, still the router, still the line.
They keep this up until you just give up.

I've just spent a week compiling a comprehensive report to our IT Director about Daisy and I'm pleased to say that we're migrating away from Daisy.

Thank god! for gods sake, do not touch these cowboys.