[PayPal Subscriptions]

You can't cancel it yet leave it active. The customer would have to be charged $9.90/m or you'd have to cancel it and have the customer setup a new subscription when the time is due for the correct amount.

If Blesta implemented billing agreements, this wouldn't be a problem: 

https://requests.blesta.com/topic/paypal-billing-agreements

[Offline Payment I Do Not Understand]

On 9/27/2017 at 2:58 PM, Nextop Host said:

I have explained in my post. When client choose offline payment option, they'll be redirected to instraction page. Below the page there will be a check box to confirm they read the instration. If client mark/select check box, a form with several input field will be shown like Client ID, Invoice ID, Bank/Mobile payment option (dropdown), Transaction ID or Bank Account Number etc. After filling the form, client will click on submit button and a support ticket will be created following the submitted form under Manual/Offline Department. This will be helpful for admin to check offline payment immediately after it has been paid by client.

The module isn't that feature-rich and likely wouldn't cover your needs here. What you can do is look to add a feature request (http://requests.blesta.com) or consider custom development (https://www.blesta.com/development/).

[Multi-Company License Set-up?]

All of your addon companies are associated with that single license so it wouldn't be a separate one for each. Most likely your license just doesn't yet recognize the addon company associated with your license. To fix that, you can try revalidating your license by visiting /admin/license in your browser (replacing /admin/ with any custom admin directory if you have one set).