Hello Parry,
I have known a lot of Indian and Pakistanis who owed loads to banks and credit card companies and while returning home did not pay the dues. Some were unfortunate who lost their jobs and had to return in an emergency but there were many who borrowed with the intention of not paying and seemingly got away with it.
Then there was a crack down both from with in Saudi and UAE in early 1990s and 2000s ( or all of the middle east for that matter) . before leaving for good one needs a police clearance report which requires you to clear all of your dues and utility bills. The ones who left on an exit re-entry visa and failed to return were chased by private contracted companies for recovery who were notorious to use illegal means to recover the money.
let us come to your specific issue. If you are receiving calls or messages from these individuals, you must not feel threatened. you must communicate with them and try to get their complete whereabouts , phone numbers and possibly address and report them to the police. You should also seek advise from a competent lawyer and work under his guidance.
Once you have agreed to repay the loan ( fully, partially or in installments) , you must not make the payments to an intermediateory party in your home country. You should communicate directly with the lending bank through a friend or a family member and remit the funds officially through banking transaction.