I am sorry you have not had your answers to your questions answered. I try to get back to my shoppers ASAP. I even give out my phone number and hope that shoppers only call if it is really important.
The big problem is that when you are working for a larger company, sometimes there are so many emails that the scheduler may get overwhelmed and put emails into answer now and later lists. Some schedulers get hundreds of emails a day and that is why you may get an answer of yes , no or thank you, etc. Very brief and to the point. the scheduler just tries to get as much done as possible without taking too much time on one email.
I would hope that most schedulers answer their emails, but as a shopper myself, I know emails are not answered. The shop you may have asked about may have been scheduled already and instead of sending a quick note that it is already scheduled, the person may just dismiss the email, sorry. Or they put you in a back up list if a shopper flakes and they need you later on.
There are a lot of things that can happen. Please remember that a lot of schedulers are IC schedulers and this means they work from home and work around their family's schedule. Some have small children, etc. The office schedulers may only work office hours. IC schedulers you will find online at all different hours of the day and night. We work when we have time or there is a need.
I hope this explains the issue. If it is something really urgent you have a question on, say how to do something on a shop you are completing and you didn't get a response, try and contact the main office if you can find a phone number for the mystery shopping company. Your scheduler is your first stop, but the MSP office is always a good second way to get answers. It will also alert the MSP if the scheduler is not answering his/her emails.
I was waiting for days for a response from the person I was working for. I got really upset I didn't get a response. I found my email had gone to her spam email and she wasn't checking her spam email. This is something that happens as well unfortunately.