expected_payment_date = datetime.date.today() + datetime.timedelta(-int(2))

users = Payment.objects.filter(expected_payment_date=expected_payment_date)

I think it will not work because it creates a datetime object with time values set to 0, so the time in database doesn't match.

With the above code you might get just Payment object list which is overdue from last to days, what about if there are overdues from more than 3/4/5 days ??

If you want date between the range like, from start of the current month/year to (current date -2 / day before yesterday/ overdue by 2 days) you can do as follows by using greater than equal and less than equal :

import datetime
from datetime import date
from datetime import timedelta

startDate = date(2017, 1, 1) # start date
endDate = date.today() - timedelta(days=2) # end date --> day before yesterday.
payments = Payment.objects.filter(expected_payment_date__gte=startDate,
                                expected_payment_date__lte=endDate)

Other Way: Simply you can use __range,

        startDate = date(2017, 1, 1) # start date
        endDate = date.today() - timedelta(days=2) # Day before Yesterday.
        Payment.objects.filter(expected_payment_date__range=[startDate, endDate])      

NOTE: There should be a Boolean flag in the Payment model, which will tell if the payment is paid or it is due, say we add isDue flag in Payment, then when you get payment set it to False, till you get the payment it will be True. then you can do like:

Payment.objects.filter(expected_payment_date__range=[startDate, endDate], isDue=True)

I was using a + sign instead of a - sign

expected_payment_date = datetime.date.today() + datetime.timedelta(-int(2))