Factory Unlocked iPhone 4 not working with a different SIM

[girishramarao]

Recently, I bought a factory unlocked iphone 4 in Australia and brought it back to India and activated the phone through iTunes using an already trimmed SIM(since there are no Micro sims available in my country) of 'Cellone' Carrier that I was using for my iPad since quite some time.
The phone got activated without any issues and I was able to use all the functionalities of it. However, my 'Cellone' SIM is meant for data usage on my ipad and for regular calling purpose, I want to use my 'Airtel' Carrier SIM. Hence, I have trimmed my Airtel SIM to fit into my new iphone 4.
However when I insert the Airtel SIM, the phone is not recognized it and shows the "No SIM" message. I'm very sure that I have properly trimmed the Airtel SIM because when I insert the same Airtel SIM in my Ipad 3G, Ipad recognizes it properly and I'm able to browse the web.
Also, on my new Iphone 4, I have inserted another Micro SIM (apart from the Cellone SIM) which it recognizes properly. All that the issue is it is just not recognizing my Airtel SIM.
This being the situation, now I have gone clueless. Firstly, I was under the assumption that Factory unlocked iphone allows to use only one carrier SIM (in my case the Cellone SIM). However, it seems my understanding is not correct, since the phone recognizes another Micro SIM. Any help in this matter is greatly appreciated.
Thanks much in advance.

 

[Gregoris]

sounds like an issue with the carrier, you should ask them for a micro sim instead

 

[girishramarao]

Thanks..In fact it was an issue with the SIM itself. Got the New SIM from Airtel, tirmmed it and now it works perfectly fine.

 

[Gregoris]

excellent