I don't get all mushy on people so I'll be blunt.. might wanna save up to pay off your debt instead. I hope your next roommate will be a more reliable person.
I'm doing both, trust me. Paying off the rent is the most important but doing NOTHING while I do that would be bad for my mental health. I'd be sleeping at night, walking the town during the day (or staying at the nearby grocers for wi-wi), and only thinking about the debt my sister left me with? No, thank you.
Doing one does not prevent me from doing the other. I just have to plan on saving up instead of just buying it when it comes out.
Edit: And I'm not going to have anymore roommates.
My first one took advantage of me, fractured my ribs, and broke 8 of my teeth while convincing me I was a failure & draining my bank account over the course of 6 years.
The second one (my sis) could not pay her part of the rent without being treated like a child. She has left me ALL the debt and does not even offer to pay for half the storage fees that hold BOTH our furniture.
I'll quite happily live alone. I'm all roommate'd out.