I purchased Sonar Platinum subscription on Steam at march 2015 by using my bankcard. Mountly subscription amount was taken till September 2015. I have used my sonar platinum and i got all  the updates. But After september 2015, i have seen no subsription charges at my bank account. And Now i can not use my Sonar Platinum!!! All my projects stoped. And also I can not get the kingston update. When i want to run Sonar, i get "error message" and it doesnt run. But i still see Sonar Paltinum at my software list in Steam. And also when i want to go on my mountly subsription, there is no such a choise now. Steam want to take full amount of Sonar Platinum! I sent 6 mount subscription money...!!!! Acording to my mountly subscription agreement, when i pay 12 mount subscription, i am gona get the full program. Please help ASAP, because All my projects STOPED!!!

No offence, but it sounds like you need to take that up with Steam.
Or just buy Sonar with a one time payment while it seems to be on sale right now (audiodeluxe/jrrshop/cakewalk store), which might be a better deal.

Steam stopped doing the subscription model in October.  However, anybody who had been paying for it should have the full version of whatever version they had showing in their Steam account as a "complimentary licence".  
 
What this means is that now to get updates you will need to do your subscription directly through Cakewalk, but you should get it at the discounted rate as you now have the full version of the program.  But as I understand, you will need to uninstall the current version that you have through Steam, although this won't affect your projects as they are in a seperate folder entirely and when you reinstall it again Sonar will find them.
 
As for the other issues you've had, I don't know what's caused this.  I also purchased Sonar on subscription through Steam but don't have any of the issues you've mentioned.  Mine still works fine.

Thank you friends. I am gona unistall and reinstall it.

nebukenazar
I purchased Sonar Platinum subscription on Steam at march 2015 by using my bankcard. Mountly subscription amount was taken till September 2015. I have used my sonar platinum and i got all  the updates. But After september 2015, i have seen no subsription charges at my bank account. And Now i can not use my Sonar Platinum!!! All my projects stoped. And also I can not get the kingston update. When i want to run Sonar, i get "error message" and it doesnt run. But i still see Sonar Paltinum at my software list in Steam. And also when i want to go on my mountly subsription, there is no such a choise now. Steam want to take full amount of Sonar Platinum! I sent 6 mount subscription money...!!!! Acording to my mountly subscription agreement, when i pay 12 mount subscription, i am gona get the full program. Please help ASAP, because All my projects STOPED!!!

I saw your post over on STEAM and replied there as well: http://steamcommunity.com/app/293140/discussions/0/494631967665193812/#c494632338490085298
 
Can you please expand on the "error message" that you are receiving? This is just not enough information for us to offer you a proper resolution to the issue. 
 
All 

kevmsmith81
Steam stopped doing the subscription model in October.  However, anybody who had been paying for it should have the full version of whatever version they had showing in their Steam account as a "complimentary licence".  
 
What this means is that now to get updates you will need to do your subscription directly through Cakewalk, but you should get it at the discounted rate as you now have the full version of the program.  But as I understand, you will need to uninstall the current version that you have through Steam, although this won't affect your projects as they are in a seperate folder entirely and when you reinstall it again Sonar will find them.
 
As for the other issues you've had, I don't know what's caused this.  I also purchased Sonar on subscription through Steam but don't have any of the issues you've mentioned.  Mine still works fine.

This is incorrect. All STEAM users are still seeing updates and will still see updates till the end of their original subscription start date.

If a STEAM user wants to continue with a subscription payment plan after updates stop, you'll need to move directly to Cakewalk.

Full purchase options are still and will still be available in the future for customers who want to stay on STEAM.