Expense of rs. 50,000. is it disallowed?

I have made purchases on credit. And I made payment through a crossed cheque of rs 50,000.I l came to know that under section 40A(3), the payment above 20,000 is to be made by account payee cheque. But I have croosed the cheque but not written account payee there. Will it be disallowed under this provision despite the fact that the supplier didn't endorse the cheque further? Please help.