IRCC says it doesn’t provide acknowledgement of receipt (AOR) for paper based applications. They will advise you to submit an electronic application which in my opinion is an avenue to exploit applicants! The other thing is that they will send you those generic emails saying you have maintained status but it doesn’t indicate that you have applied and that they have received your application! So that is as good as useless! The last viable option is to explore ways to link your paper based application to your online profile. But this will require you to have your file/application number. Next best step is to call IRCC and ask if they have since created a temporary file which has an XW plus some digits.If you get hold of that number, then you can use it to link your paper application with the online profile. I have been through this since December 11, 2023 and I fully understand your frustration!