hi, wala nmn problema kung naka 4G SIM ka kung 2G/3G yung phone mo.
you have to change lang yung signal sa setting ng phone mo from LTE to 2G/3G para magamit mo signal ng phone mo
then kung may 4G phone ka nmn you can use yung 4G ng phone
Phone | Sim | Area Network = Network that you will have
4G | 3G | 4G = 3G
2G | 3G | 4G = 2G
3G | 3G | 3G = 3G
3G | 4G | 4G = 3G
As you can see, magfafallback ang network na magiging available sayo sa availability of the three factors listed above. So it's perfectly fine to have a 3G phone even if you have a 4G sim. You can try to troubleshoot your phone first by turning it off and on first, then try as well to do a manual search of networks. You can also try to so this to see if it will work for ya. Go to Settings > Mobile Networks > Mobile Data > Mobile Data Network > WCDMA only. Hope this works
You can also try to call the hotline if you need further help.
Kaya wala pang signal yan kasi di pa activated yang plan mo. Kahit 2G/3G lang ung phone mo at LTE naman ang sim, gagana pa rin yan kung activated na ung plan mo. Paactivate mo lang yan sa malapit na globe store.