i found my phone after claiming it lost

The right thing to do is back up your data if there are any and then return it to the insurance company.

BUT if you think you would like to get another line on this phone then you can call tmobile ask as them "I have found my lost phone can you please remove it from the blacklist and I will line to add another line to this device". If your phone was bought from tmobile they will be able to verify you as the owner and clear the device for you. Once the device is removed from the blocklist its no longer a stolen device. 

If you do this intentionally to defraud the insurance company, then you have committed a crime. If the insurance company figures it out they will take legal actions against you for insurance fraud. And people did get caught in past, The incident that I personally know about  a person did this on 3 devices that was on a family plan all three claims in the same month and canceled the insurances after receiving the replacement device. That guy was fined 5000, and got 500 hours of community service. He was lucky not to get jail time. But also lost his job and now have a criminal record on his history. 

I think you need to return it as soon as possible

Luby wrote:

Hello, i lost my phone and I claim it as lost, i got a replacement and get the new phone running. Then I found the lost one. What should I do? Do I return it or I can get the old one unlocked and working?? Please advise

Just be aware of what might happen if you do the right thing.

How do you find out where the last place my iPhone was at because I believe somebody stole it 

BigScoot wrote:

How do you find out where the last place my iPhone was at because I believe somebody stole it 

https://www.apple.com/icloud/find-my

Why is everybody obsessed with the insurance company? What if you got a new phone after one was stolen, 6 months later miraculously get it returned to you but you can't remember the passcode to get in and it's not showing up on find my phone? Forget about the insurance company, focus on these questions, the phone was bought in full brand new unlocked off of eBay. T-mobile is simply service provider

If the phone was reported lost or stolen then the phone is blocked and basically a brick and unable to use on another carrier.

gramps28 wrote:

If the phone was reported lost or stolen then the phone is blocked and basically a brick and unable to use on another carrier.

I don't want to use it with another carrier though. I want to keep using t-mobile, I just don't know how to get it unlocked. Only my new phone shows up on find my phone or else I would unlock it on there. Although, just to point out,  like I said, I bought it factory unlocked so it's not tied to any carrier but since I want to continue with t-mobile how do I get it unlocked? The phone is still on and it rings and has service since it's been getting paid even though it was stolen. 

You need to contact Tmobile support by calling or using messenger on one of T-Mobile’s social media platforms to see if they can help.