Provision if GST rate on input is more than GST rate on Output?

The scenario mentioned by you is could be called as 'inverted duty structure' whereby rate of tax on input goods/services is higher than rate of tax on output goods/services.

Also, you can go for refund of accumulated credits if credits are accumulated as input tax rate is higher than output tax rate. 

Please note that there are certain sectors where this refund is restricted by government e.g. construction.

GST Provision-

Section 54(3)- where the credit has accumulated on account of rate of tax on inputs being higher than the rate of tax on output supplies (other than nil rated or fully exempt supplies), except supplies of goods or services or both as may be notified by the Government on the recommendations of the Council: