Company asking to return laptop, which I hasn't been delivered to me.

I joined an MNC in Pune. They dispatched me a laptop in September . Although I was aware of this, but my phone number was out of service during the delivery time. Now, due reasons I wasn't able to join the company as a full time employee. I did 2 days and then stopped attending. I thought that since I am probation they would automatically fire me and they did. So I didn't give much thought to that and was busy dealing with current family issues. Then one day I received a call in December in which they asked about the Laptop provided. And I told them that I received no such delivery and that my number wasn't on Due to lack of balance. I received a call today they are saying that they would take further action if I do not return the laptop which I haven't received. I tried my best explaining the situation but they don't want to hear anything. And I have no written proof of notifying the company about the issue, as I only notified them orally on a call to I don't know whom.What should do?