Use of is and has: More than 20 days have passed since I applied for PAN, but...

[Bhushan]

Dear Sir,

Please guide me on the following sentense

" It is more than 20 days have passed since I have applied for PAN but no intimation is received yet."

or

More than 20 days had passed since I had applied for PAN but no intimation has been received till date

which is more appropriate or you may suggest other one.

[Mister Micawber]

.
These are OK:

More than 20 days have passed since I applied for PAN, but no response has been received yet.

It has been more than 20 days since I applied for PAN but no response has been received yet.
.
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Native English teacher at Mister Micawber's