What what I can make out of your post which has all bunched up together @antsAdebs your phone has “crashed” and was sent for repair.
Did Samsung say what had happened to cause the crashing ?
And now it's happening again and you want a new phone ?
In that regard you would need to speak with who supplied the phone and look at their Terms and Conditions.
In the UK if the phone is under 30 days then a person can request a new replacement.
If over 30 days then it's a repair.
This maybe different where you live.
Generic troubleshooting tips are …
1. Clear your phone's System Cache Files by turning your phone Off and then from a set series of button presses go into the phone's System Files and clear the cache. No information is lost this way. You may need to insert your headphones or hook upto a computer with your data cable to get to this menu on the phone.