What should I do? Do I have to go to Putian to apply for opening a mobile phone?

If the number has been out of service for more than 3 months and has not been activated, the number will be removed for recycling. (that is, sell it again). Even if it can be opened in Putian now, it may not be possible to get that number back. If the number is out of the market again, you can't go to every place in Putian where you can buy a mobile card. Even if it is found, it may be bought by others. If you are really nervous about this number, you should not retire for more than two months. If you really want it, you can wait for someone to use this number and buy it back at a high price.