How can I switch my billing cycle from yearly to monthly?

[JoniMurphyArtis]

Hi, 

I need to change my plan from yearly to monthly.

How can I do this? 

Yearly amount ($348 USD + GST = $600 NZD) is out of my reach this year. - Artists are struggling at the moment, cost of living crisis etc.
I was billed on 20 March (today) and my payment failed. 

How can I change the billing cycle from yearly back to monthly? 
There is no option other than to pay the yearly amount, before I can make any changes to my billing cycle. 
If Shopify bills ‘in advance’ then I feel

I shouldn’t be forced to pay a whole year in advance, I should have the option to go back to paying monthly? 
I want to avoid my website being frozen! 

Any ideas will be welcome

Thanks