Had a steady speed of 40mbps for the last few weeks and upload of 8mbps. Had a power cut yesterday but when the power came back on my speed has been up and down. sometimes 16. Tried the online fault thing in my account and it says there is a problem and to talk to customer services. Could you look into it for me please?
The line tests have not detected any faults and your line is in sync at 42.1mb.
Please can you power down the router for a full 30 minutes and then run a speed test following this?