is there any support center at bangladesh?

There are a couple of Apple service providers in Dhaka. I found these two through the online lookup:

EXECUTIVE MACHINES

183, GULSHAN AVENUE

DHAKA, DHAKA 1212

ISERVICE

SHOP#4B-007, BLOCK#B, 4TH FLOOR, JAMUNA FUTURE PARK

KURIL, PRAGATI SARANI

DHAKA, DHAKA 1229

Also, in some regions Apple doesn't actually provide direct repair of any devices because of a lack of the calibration equipment to complete the job. They would provide service replacements for a general cost of repair, and the exchanged device would become property of Apple to have repaired/refurbished and then recirculated as service replacements. If that's the case then it might sense to have it backed up.

Hi Riadmahmood,

Thanks for reaching out in Apple Support Communities. I understand that you'd like to have your iPhone examined due to issues with the display separating from the case. I can see why you'd reach out about this; I can point you in the right direction. While it's not possible to determine the cause of the display separating from the enclosure, you're on the right track with wanting to have the device examined for the options available. I'd recommend using this resource to find the nearest Apple Authorized Service Provider to have your iPhone examined: Find Locations

Best Regards.