Mobikwik wallet locked pls help

Dear dimers ,
seeking your assistance/suggestion on the following issue;

Mobikwik and Microsoft Lumia advertised an offer where in buyer of Lumia phone would be eligible for Rs3600/- cashback (Rs.300/- per month) using LUM300 code. As per the offer, buyer need to register on Mobikwik before 15 November 2015, and add Rs300/- to Mobikwik account using promocode "lum300"code to get a cashback of Rs.300/-.
The link with offer detail is:
https://www.microsoft.com/en-in/mobile/campaign...
Myself and my wife bought two Lumia phones during this offer period, in October 2015 and registered with Mobikwik for availing the Lumia (LUM300) offer.
We both husband & wife availed the offer for first three months, October, November and December 2015. Both our Mobikwik wallets have our money (which we added to avail the offer) plus the cashback provided by Mobikwik as part of offer.
The problem I noticed in Mid December while trying to make my electricity bill payment using Mobikwik wallet, I found my Mobikwik wallet has been blocked with a message saying “ account disabled due to suspicious activity. Contact validation@mobikwik for reactivation".
I checked and found my wife’s account is also blocked.
I contacted Mobikwik and was told to provide photo id card, address proof and bank statement showing Mobikwik transactions . I duly provided Photo Id card, Voter id card and Bank statement.
However, no response came from Mobikwik and our accounts (wallets) with our money remained blocked.
After several attempt and several days I came to know from the Mobikwik Customer support on twitter, that both our accounts are blocked as same credit card has been used in both accounts. I was told that I have violated one condition of the offer which reads:
"Offer can be redeemed only once per user, per month, per card and is applicable for the “Add Money” payment done during the offer period on MobiKwik App Only"
I submitted that its an oversight on our part and out of sheer ignorance my wife has used my credit card on her Mobikwik wallet account. I contended that since the offer says its once per card, Mobikwik at first place should not have allowed the offer to be availed twice on the same card. However, I further submitted that if Mobikwik wishes, it may revert back the cashback it has credited as part of offer, from one of the account as Cashbacks are not utilised by any of us.
My contention is, since none of us (me and my wife) indulged in any illegal, fraudulent activity, nor violated any T&C of Mobikwik wallet, our wallets should not have been blocked. Mobikwik can at best deny/forfeit/revert the offer benefit (cashback) from any one of our accounts, for the month in which same card was used in both account.

I know its a mistake on our part to not read the T&C of offer fully. However, isn’t my contention right? The violation is limited to the offer T&C .

Thanks for reading a lengthy post. expect fellow dimers to guide me out of this troubled water (created by myself I admit )