LIME-438: Add buying suscription using points

[DavidCharif]

[ArtemLymarenko]

I think you misunderstood the task

1. If user has subscription you have to propose user to buy 1 month for coins and after that 1 month user subription will be automaticly charged on the next billing cycle. So user can additionally buy 1 month for coins
2. If user don't have subscription and buying it for points first time you have to create one and set trial period. In the furure we are doing that same as in step 1.
3. If you want change your subscription by coins you have to cancel previous one and create new with trial period.

As I see in your code you just creating new subscription with trial period and don't update existing one.

[DavidCharif]

[DavidCharif]

Invoice will arrive, but will be on Zero