Sms Lane — sms credit deducted

Address:

Nalbari, Assam, 781335

Same as morrakesh
Sms lane is a very big cheater company. They are fraud. I was cheated by them by deducting sms from my account all of a sudden without any information.
I purchase 5 lakh sms from sms lane in dec 2017 while now in may 2018, they deducted 290539 sms from my account all of a sudden with no mail or call to me. When i contacted them, they refused to credit the sms back in my account making an excuse of price hike.
And the credit is not short. Its a huge amount.
How this hike can be applicable on a customer who purchased before. For new customers this is valid.