Unstable connection & my telephone line

[zq120]

Not only becoz of the recent cable cut, my bb connection is very unstable i often got disconnected.I changed dns and sometimes it worked.This morning i could not get the connection during free period.It worked on 10:30.I thought this is normal for bsnl (bsnl sucks but we have no choice here).How often do you get disconnected?Also my telephone line stops often (no sound),when that happened i dial the phone number from my mobile and it rang and work after (after lifting the phone two or three times).At 6 pm today it stops again and to my amazement i hear voices when i rang the phone from my mobile.Can there be any foul play in this? Dynamic locking also not working.