"No service" after replacing battery

I replaced original with 1600 mAh and lost the aerial signal the next day.

It works when in certain areas only.

I tried reset network and restore of system.

I tried disabling 3G and it would work intermittently.

Any ideas?

How to fix the Iphone 3GS " NO SERVICE"?

I had problems connecting #7 and had to tape it down as it wouldn't lock. I will take a look with a magnifying glass and try to correct the connector.

There is a pointed piece beside #7. Should it come in contact with the metal casing?

I have sporadic service in selected areas of Toronto (such as near Rogers head office).

When i installed the battery, i noticed the "do not remove" paper had been removed and re-attached and the #7 clip didn't reconnect easily.

I have a feeling the phone was reconditioned and not new when received.