Since Symphony's Instagram ads run directly through your Facebook ad account, you have full control over how often you're charged and which card / payment method you'd like to use.
On the "Review" step of Symphony's Instagram ads playbooks (Increase Music Streams, Boost Instagram Engagement, Increase Link Clicks), you'll be able to see the payment method linked to your Facebook Ad Account.
If you click the arrow next to the payment method, Symphony will open up your Facebook "Billing" settings:
Within your Facebook billing settings, you're able to set:
which payment method you'd like to use for your ads
how often you'd want to be billed (based on Facebook's Payment Thresholds)
and account spending limits, as well as download any invoices
For example, if you set your Payment Threshold to $50, Facebook will charge your payment method every time your ads reach $50 of spend.
