Indraprastha Gas Limited [IGL] — bill payment of rs. 1851.73 sent my mobile no. but online payment it shows excess amount.

Address:

Ghaziabad, Uttar Pradesh, 201013

My bp no. [protected]. I got a message on 30.05.2018 at 2 p. M. On my registered mobile no. [protected] that payment of rs. 1851.73 dated 24.05.2018 is outstanding. Immediately, i want to pay the same but online amount shows rs. 1888.45 (In excess of the amount shown in my message).
I such condition, why i pay excess amount of rs. 1888.45 while i got message only on 30.05.2018 at 2 p. M. Please resolve the matter immediately.