service detoriated after changing to fibre package

I have been a happy p.n customer for past 12 months on 38mb fibre getting 37 mbps so decided to upgrade to fibre extra thought I'd bump the speed up to 70 or 80 mb the profile change went through over night an today found out they throttled me back due to supposedly unstable line,which I know it's not true as been stable past 12 months was on fast path up an down now that's changed to up only an interleaved down does anyone have a ideas why they would do this when it was only a profile change to do

What speed was estimated at the point of sale, and what what speeds are the modem connecting at?

The change of product means the DLM system is invariably reset and thus the line needs to be profiled and this may mean speeds of 70 Mbps in the first day or two drop to lower speeds.

A stable 39999 Kbps sync line does not guarantee a stable line once the sync cap is removed.

p.n email said call achieve between 67 an 80 mb d.n

Well what speed has it connected at?

current conf stats are

d/L 37.1mb
u/l 10.1 mb

plusnet say I should be getting the following

d/l min guaranteed 60 mb
u/l 20 mb

Guess it might be a dlm retrain so guess 3 day wait

Configured where? Rare for a router to report 37.1mb can you copy and paste from the routers web interface

Such a low speed suggests not DLM but something else going on, what were the stats before from opening post one would presume 39,999 Kbps downstream sync speed - if your sync was below that then upgrading would NOT have given any extra speed.

Does the 10 up the OP reports not imply his line is connected to the wrong service, or that PN have him on a 40/10 service ?

It might, it might not we have very few firm details to go on.

e.g. it could be the sales estimate was wrong, or poster recalls an advert rather than a sales estimate, or they were plain mis-sold the service.

OR

service is still configured as 40/10 somewhere e.g. in the PlusNet side which can be a bit sticky.

To unravel the puzzle a screen shot of the actual sync speeds (screen shot to avoid any typo or missing important info) is needed.

If there is a worry of a mis-selling then again sync speeds from before and after and a location for the poster is needed to assess that.