I have filed my Income tax return and got my refund, but When I signed in to CRA, it says that I am not getting GST/HST credits whereas I am eligible for it

In your CRA My Account go to "Benefits and credits", then "GST/HST credit", then "More information" - there should be a reason as to why you're not getting GST/HST credit. If you have a spouse/partner, it is possible that they're receiving the credit and only one person in the family can receive it.

Thank you for choosing TurboTax.

I have checked but they have not mentioned any reason for the not giving GST/HST credit and also my status is single.

To clarify the reason you were not eligible, please call the Canada Revenue Agency (CRA) at 1-800-959-8281.

Thank you for choosing TurboTax.