Help for Email and Fopen

[eluser]paullo[/eluser]
Hi,please i worked on a project that save people's data and give them a response message using CI,in which the response message is usually in email and text message format.

And my site connect to another 2 other site to complete the operation,but since about 2-3 days ago now,the response is no more active and people are complaining bitterly.

Please what could have been the problem?because i checked the script including the url_helper script that does the linking there is no problem in it,or could it be from my host provider?

Please i want immediate response.
Thanks