Very bad experience with Teljoy

I am ex colleague who worked for +-3 years with Teljoy and in 2014 rented a fridge with my company and deductions were done monthly and included on the payslip. I never missed a payment and 2018 July was supposed to have been my last installment month. In 2017 October I resigned from the company and necessary deductions were made. To my surprise this year 2018 May, 7months later, my mom gets a call from Teljoy accounts stating they want my number they need to collect the unit because I haven't been paying for the past 7months. My mom gave them my number and I get this shocking call from Teljoy, some Malathy lady calls and says I'm owing and they coming to collect my fridge. My first question was how can you not have my number, I'm an ex colleague. Secondly the instalments were deducted from the payslip and not from my account, did it ever occurred to HR or accounts that I'm about to leave the company and make necessary arrangements of paying my monthly instalments with me? She couldn't answer obviously, then 7months later they start with the threats of collecting my unit. I am extremely dissapointed because all of this could have been avoided should someone had done their job, hopefully this predicament doesn't happen to someone else. Now monies I don't have "must" be paid or else.