Internet dropped out after engineers visit

[Dave2410]

We've just had a BT engineer out to check the line as the sky engineer that visited a week said the issue is with the line not the router. 
BT engineer visit today and thought the problem was solved as he repaired damage to the line. I witnessed him checking the line and had download speed of 41mps. However 10mins after he left the internet dropped out and only have a download speed of 1.7mps. Resets of the router have been carried but nothing has changed. 
After carrying out speed test there's no option to request a revisit by an engineer to further diagnose the fault.