Synchrony Financial Credit Card Complaint

Synchrony Financial Credit card department,

Balance transfer Idaho

i am being charged a very high interest and have got a 0 % interest on balance transfer and they will not allow me to make the payment with a credit card. so i was going to have the card company send them a check but in my account info i have no account number have never received a card and they refuse to tell me over the phone my account number. i do not think it is appropriate for them to keep all my info from me since i am the one being charged with high interest.