Hello,
I found Lime survey THE solution for online survey. It is easy and full of feature. I have one CRM developed by myself that has few modules like ticket assistance and invoicing. It will be useful if:

1. I can create one generic survey for assistance that has no ending date but with no public access
2. I can add by API or by Database-written to Lime survey one user every time I complete an assistance and
3. Lime Survey ask by e-mail to this user to complete the survey regarding this assistance or invoice.

I don't know if

1. There is a API for Lime Survey for this thing
2. Because the same customer (same e-mail) can have multiple assistance request, can Lime survey accept user with same e-mail?

Thanks for the information

1) Please refer to the manual - manual.limesurvey.org/RemoteControl_2_API

2) Please refer to the manual - manual.limesurvey.org/Tokens