How to restore my text massages after they exported

Hello everyone!
I exported my text messages before I restore my phone as it's how I usually backup my contacts. With contacts, I've had zero problem importing them back to my phone. This time, I backed up my messages by exporting them through the app on my phone. it zipped the file. when I unzipped it, I see two files but they are not xml file, nor they have any extension. there is a site that categorized them as Java serialized data version 5. I was wondering if anyone knows how to restore the messages. If I open the smaller file as text, I can see the texts and the phone numbers out of order, along with some weird symbols. Thanks for your help.