Hi there Iang43, welcome to our forum and thanks for your post.
Sorry to see you are having issues with the signal on your mobile. So we can assist further can you please confirm the following:
-Is this happening indoors and outdoors?
-Do you see this issue in any other areas?
-What handset are you using?
-Does the issue occur when you have used the sim in another phone?
-Are you having the same issue on calls, texts and data?
As well as clarifying the above, have you been able to check the coverage checker here to see what the signal in the area should be like?
It may also be a good idea to go through some checks on our phone fix section of the website here to see if there is anything further to help.
Please let me know if you need any further help with this.
Regards
Nathan