Airtel — recharge done for 84 days now customer care says pack was of 70 days

Address: Ghaziabad, Uttar Pradesh, 201001

I did a recharge on 19 july of 399 for 84 days. But my plan got finished in 70 days. After inquiring on customer care they said my plan was not for 84 days, it was of 70 days. But i clearly remembered that my recharge was for 84 days.
I did the recharge on two other numbers also of 84 days but for those two also customer care is saying that it is of 70 days.
They have not mentioned anywhere that the validity is 70 days or 84 days. Neither is the message nor it is showing in their my airtel app or on their site.
Its clearly fraud. First they show that ur validity will be 84 days before recharge.
After recharge they dont send any detail regarding validity. Then in between they lower down the validity o[censored]r pack and say that same pack is still available on ur number.