OK, let's talk the other way - did you read news and announcements re: new payment methods?
If you had error using Interkassa, and if you are not satisfied with Liqpay (with regard to security and safety of your CCard), have you tried
www.paxum.com (which is Canadian system analogue of PayPal) or Liberty Reserve?
Why are you talking about only Interkassa and Onpay (or Liqpay) then? TRY OTHER ALTERNATIVE METHODS introduced specially for foreign users living abroad Russia. These methods were specially introduced for you, and you don't want to use them? OK, let it be be your problem, and don't expect any other assistance in payment. We are not Liqpay, and we have no idea why it causes error for you. Use Webmoney, use anything you like...
regards