Avoid using started state, as it is impossible for customer to move Payment
Transaction into this state.

Just use planned and confirmed states and synchronously try to move to confirmed
when user tries to access the transaction.

Support a case when customer will leave Vifib.net site but will not finish the payment.
In such case just propose him to pay again the transaction, and if required, setup
newer PayZen integration id (eg. in case of big, like a day, delay).

In case if transaction was proposed to be paid and user sucessfully paid it before
update immediately transaction status.