VRL travels review: Refund of difference amount

Travelled Pune-Amravati with T R # 1556096 .
Two tickets (Pune- Amravati) for AC sleeper was Rs 2200-5% discount was booked.
Due to some technical problems in the bus a volvo seater bus was sent that also 2 hours delayed. The tickets for Volvo seater was 1600-5% for two travelers. All the customers argued with the local representative... asked to refund the remaining amount(Rs [protected]=600-5%) and he agreed that the destination office (Amravati) will refund it...but all invain.. he refrained from the payment as it was out of his jurisdiction as the ticket was booked online

When asked the head office for the same.. they made all possible excuses to avoid the refund.
I have been taking a follow up on the issue created with no success... finally writing here.
Please help!