Normally, a KoBoToolbox representatives may not reach you out but if your project is affecting the server’s load balance you may be reached. Generally huge data collection from a single user may affect the server’s performance.
Regarding your second query on the total number of variables, you may have issues while loading your survey project with a lot of variables. Thus at this point you should understand that your survey project may have a large number of variables in it. Maybe this post discussed previously should help you understand what happens if you have too many variables for a survey project:
