I am a new sify broadband customer

Hi All,
I am a new sify broadband customer.
I have read the comments regarding the sify service, so it seems the service is not efficient.
But in our locality as there is no other service I was forced to opt for this.
I have a query regarding some problems.
Sometimes at night I am getting the problem
” System Error: Ip address conflict:
there is an IP address conflict with another system on the network ”
Could anyone tell me what might be the reason for this type of problem, so that it helps to troubleshoot this problem or else is this error lies with the service provider.
I never changed the IP Address on my system when this problem occured.
Looking up for your support……..
Thanks,
Vijay