10 Mbps would be considered slow for your line.
Looks like a banded profile has been applied to the line. The line attenuation and noise margins give an estimated speed of 16550Kbps to 18750Kbps
Link to full estimate
Support should be able to spot this themselves, particularly as there is lots of spare noise margin available.
Phrases that might help with decent telephone support:
There was some line instability that has resulted in my line being banded, can you reset the banding and get the line to restart its learning profile.
If you don't improve my speeds in the next 2 weeks I will be calling back to request my migration code and expect to be released from any contract terms if there are no significant improvements.