Airtel — pack related issue.

Address:

Solan, Himachal Pradesh, 173205

09 jan. 18
I take a pack of 399 on 30 oct. 17 valid for 84 days.
On 09 jan. 18 12 days pending of this pack.
Now i retake a pack of 509 on 09 jan. 18 they deactivate my previous plan on the sport and activate new plan.
I recharge by airtel app no any this type is mention that old pack is deactivate by take a new plan.
I call on 198 but there service is very bad.
They talk will other attitude, this is not to be refund or not extend any validity