POS will be the location of property. Therefore, only CGST and SGST would be levied. Charging IGST is wrong, and the company registered in UP cannot take credit of gst of Bengal.
Vendor located in West Bengal and property at UP. place of supply will be location of. immovable property which is UP. IGST will be levied. you can avail ITC.
Only in case you can take ITC : When the immovable property & you are in same state & the landlord in other state , in this condition the landlord raises the bill for rent by charging IGST & the ITC for the same can be claimed.
Note : In your case the location Immovable Property must be in UP