Sold car with outstanding finance still on my name

We purchased a car on finance 2.5 years ago. There was issues with it for months and the dealership said the only way we can get rid of it is sell the car. Few months ago we ran to some troubles and had to sell the car. Loan is currently on arrears and although we are trying to pay it off with what we can afford, the collection company has been calling us that they are outside and collecting it (no car outside the house). I’m stressed our and can’t focus on my new job that I started to help pay for the bills. What should I do?