Is it possible my ISP is limiting my speed (and usage), until i complain about it?

[fritz_le_cat]

On several occasions my internet speed has fell below half a mb.(200kbs...) and nothing i try and do changes this, scans, checking settings switching pc and router off etc. But if i call my ISP, Tiscali, or log onto their site - it instantly goes back up to an acceptable 1.5-1.9mb. it happened again today - i had been downloading a fair bit the days before, inc. some new programs. Are they trying to limit my unlimited usage account??

 

[JacobB]

you think you have problems id be very happy if i got 200kbs i only get 25kbs and i cant change it!