I have Airtel Broadband Connection with Huawei Wifi Router , TP Link RE305 AC1200 Wifi Extender I recently purchased  over Amazon India is only detecting 2.4Ghz and not detecting 

5 Ghz .
Without TP Link Extender Im able to use 5Ghz Wireless Connection with same Airtel Broadband Connection Wifi Router, no Firewall or MAC Rules or ACL is configured on Wifi Router ; checked as per manual.
Please let me know how to enable TP Link Extender for 5 Ghz WiFi Connection with my current Airtel Broadband Huawei Wifi Router.
I tried all the instructions as per tp link manual but 5 Ghz on TP Link is not getting detected.
Without 5 Ghz detection on TP Link its of no use to me. Please help to resolve this issue or I may have to return this product to Amazon India back..