How to pass third party payment gateway entries in tally erp

As per my knowledge the accounting treatment will be

letus take goods sold to ABC

a) When goods sold to ABC for 1000+5% Igst (sales entry to be pass)
ABC a/c. 1050. (Asset goesup bcoz. ABC is your S Dr's now)
To Sales a/c. 1000
To Output IGST @ 5% 50

B) When ABC made payment to CC avenue (Journal Entry to be pass)

CC avenue A/C. 1050. (Asset goes up bcoz Cc avenue is u r S Dr's now)
To ABC. 1050. (Asset goes down bcoz ABC discharged they liability)

C) when Cc avenue make payment to You. (Recp entry to be pass)

Bank a/c. 991
Input igst @ 18% 9
CC avenue service charge account. 50
To Cc Avenue a/c. 1050. ( Asset goes down bcoz CC avenue discharged they liability)

Thank You So Much Sir 

if third party refund the service charge amount and igst than what entry would be pass