recieved call only to be hung up on, but  waits till i answer

hangs up when i answer twice now

this number comes from Eco Line Windows in Winnipeg..   i had this numeber calling me many many times and all of a sudden this lady from this company is on the line. she says they use this number to call only..

Call came from this number and just hung up on me.

same here, calls in evening, hangs up, i call back and no answer!!!!