Dmtf problem?

hello, i made a system wich calls automatically with asterisk (with a voip provider), then wich was called dial a number (with some options) and it is write in a text file. I have a problem, sometimes when the user dial the option, asterisk doesn’t detect it,so the call is hanged up without write mi text file.

Suggestions??

Thanks in advance

There are lot of reasons which could be a problem - first one - sometimes some providers have problems with transmitting DTMFs. I had such problems and they were solved only after switching provider. Rarely - missing DTMFs.
Other also common problem is device it self - meaning some phones some times could not sent DTMF.
Bad Internet - also potential problem
In one case I have huge problems with occasional ignoring of DTMFs - some times after I press 2 digits fast - Asterisk stop responding at all to DTMFs - all are ignored. Only solution to this moment - is hangup and new call.