I have a situation:

A friend of mine asks me to be a guarantor/co-signer (for renting apartment). He was pretty close and reluctantly but out of goodwill I give in. Then he breaks the lease 3 months earlier and doesn’t pay the amount he owes to the apartment. Amount 1500+. Both of us were/are students.

The collection agencies call me and send me emails/mails to pay off that amount. and of course nicely remind of what might happen if u do not pay. 

My friend doesn’t reply them. He blocks off the collectors inquiries/contacts. He simply doesn’t care or says it’s not his fault (but his apartments. he says he had some issues with apartment conditions when he moved in) and tells me not to worry.

How do u deal with this ?