Minimum guaranteed speed 63mbps, but current speed drop to 43mbps, is that an issue?

[#1]

I've been with plusnet from 2013, usually speed at 63mbps, sometime even more.

but recently, I feel website loading quite slow, so I checked speed again,

tried couple of service of checking, they shows me all dropped to around 40mbps.

even on my backend of plusnet, it shows me 

minimum guaranteed speed 63.1mbps

current line speed (download): 45.2mbps

is that normal plusnet could downgrade my fibre speed such way? should I contact them for get this fixed?

[#2]

Thanks for your post @zmdehwka

Together with our network partners at Openreach we are prioritising customers who don’t have a phone line or broadband connection, meaning there might be a delay in Speed Faults being fixed.

In the meantime, please raise your speed fault online at faults.plus.net.