Internet connection keeps dying

my internet connection keeps dying and my internet provider says my connection is there but slow, my moden has the lastest updates and i was wonmdering what might cause my internet to drop if its not from my providfer

yer ive tried all that millions of times i call technical support and they say either the fax is interfering(use a splitter for fax n adsl modem) with it or the modem might be damaged i fink its the modem because it worked before for ages n the fax was still there wat u fink