Medavakkam Toll — Wrong Toll Collection

This toll is on Medavakkam to ECR route and for people going to ECR has to cross the toll road in OMR, but will be given a "No Toll or Zero Toll" slip on either side of the toll plaza which is valid for few minutes before which you have to reach the other side toll plaza of OMR. Each and every time I go to ECR from Medavakkam (not accessing OMR stretch), I've been charged one way of Rs 30 despite I getting "No Toll or Zero Toll". 22nd Nov 2020 I've used the same No Toll to cross the OMR, but I've been charged the same despite handing over the No Toll slip to the personnel. Veh Reg No MALAF51CYKM091630 and Plaza name is Medavakkam.