fixed profile ....again

ihave been having [censored] speeds etc etc
but things

have now got worse (see below )this is about the 8 time i have been put on fixed profile for no reason in the last 3 months some tomes im on it for a week or so
y??? reboots make no diffrence , no where near 40 gig limit

ADSL Description

ADSL State Show Time
Data Path Fast
Operation Mode ADSL2+
Bandwidth Down/Up(kbps) 515 / 107
SNR Margin Down/Up(dB) 17.5 / 30.3
Attenuation Down/Up(dB) 31.0 / 19.3

y does this keep happing ?
and then its ok again for a while then it happens again
and im always told there is no fault
quit apart from [censored] speeds i have been geting,