Service tax paid under reverse charge in july 2017 and transitional provision

we are manufacturer registered under excise and service tax. we have paid service tax under RCM in july 2017 for the month June 2017.

As per CCR 2004 rule 3(7) allowed cenvat credit on RCM services after payment of tax. we paid S. tax in july 2017.

We also file all return as per existing law. under section 140 Transitional provision cenvat credit carry forward if it shown as closing as on 30th june 2017.
under the circumstances can we eligible for credit or carry forward the same in GST, please provide your opinion.
or can we file refund claim?