payment processing without phone number requirement

I’ve a problem. My site are selling virtual products, so in billing field i didn’t plan to make all field visible, except name and email. Unfortunately, even after i set every billing field unset and hidden (using snippet and checkout manager/field plugin), the submission of the billing details (name and email) are still blocked

Error! Please complete your details (Name, phone, and e-mail are compulsory).

so after a while after couldn’t find what actually happen, i deactivated all the field and activated all plugin one by one to track if the problem coming from any plugin, and somehow able to tracked that even the billing form already hide/unset the phone number field in billing form, the toyyibpay plugin seems need the phone number. Is it possible to exclude the phone number requirement in toyyibpay?

thank you