Matching query does not exist/cannot assign "<QuerySet []>" - Uploading a csv file - django

I want to create a project an I need to upload an csv file to an user, but from some reason, it's not loading correctly (is uploading for the first created user, and I try do to this from others accounts).

In my view, I have something like this:

def FileViewUpload(request):  
        form = CsvFileForm(request.POST, request.FILES)
        print(request.user)
        userId = request.user.id
        print(userId)
        print(request.user.email)

        if form.is_valid():
            form.save()
            form = CsvFileForm()

            obj= CsvFileModel.objects.get(activated=False)
            with open(obj.file_name.path, 'r') as f:
                reader = csv.reader(f)

                for i, row in enumerate(reader):
                    if i==0: 
                        pass
                    else: 
                        date = row[0]
                        user = AccountUser.objects.get(contact_user = userId)
                        print(user)
                        ContactUser.objects.create(
                            date=date,
                            message= row[1]
                            user=user,
                        )
                obj.activated=True
                obj.save()
        return render(request, 'uploadFile.html', {
        'importFile': form
    })

For this lines:

print(request.user)
print(userId)
print(request.user.email)

it display the good thing, the correct id and email for that specific user. But when I press the button for upload, it's loading in the field for the first user created.

The problem, I think that is in this line: user = AccountUser.objects.get(contact_user = userId), but I don't know why, if in the beginning, at the first prints, it's show me correctly.

The model for ContactUser:

class ContactUser(models.Model):
    user = models.ForeignKey(AccountUser, related_name='contact_user', on_delete=models.CASCADE)
    date = models.CharField()
    message = models.CharField()

    def __str__(self):
        return f"{self.user}"

Edit - short update

I think that I can not access in this meaner the user that was created. I delete all the migrations, I run the commands for migrations and create the user. When I want to import the document, it gives me this AccountUser matching query does not exist, but in the AcccountUser, I can see the registration of the user, and with the print commands that was mentioned above, I see that the id is 1, and the user email. I tried to wrote the next command user=AccountUser.objects.filter(contact_user = userId) and it gives me this Cannot assign "<QuerySet []>": "ContactUser.user" must be a "AccountUser" instance.