How many people are you thinking of contacting? Survey Monkey offers a free account, with unlimited responses but you can only view the first 100 responses without having to sign up to a paid account. So it might be useful to you if either:
(a) you only require no more than 100 responses ; or
(b) you'll only be conducting your research over a short period of time. ($35 per month, which is a typical cost, soon adds up if you're using the service for any length of time but isn't too bad if you only need it for a single month).
Survey Money doesn't offer the file uploading feature that you require but you could include a question seeking permission to email respondents to request such files.
https://www.surveymonkey.co.uk/
Survey Monkey is probably the best-known way of seeking responses from people but the following sites also offer free plans:
https://www.surveygizmo.com/
(Click on 'Explore Consumer Edition')
https://www.questionpro.com/
(If you need more than 100 responses, QuestionPro might meet your needs best, as they offer an account for just $15 per month which allows you to receive up to 1000 responses per month)