network issues

I have ID mobile esim in a pixel 9 Pro. When I first had it the network coverage didn't seem quite as good as my previous provider, however, over the last few weeks coverage seems to have got steadily worse to the point that it is almost unusable and I'm having to have several attempts to complete a phone conversation. This is both normal phone calls and WhatsApp calls. I previously had three mobile and so didn't anticipate any change in network coverage. It was noticeably not as good when I first started with ID mobile but has been really poor for the last couple of weeks. This has been both at my home address and local area and the area in which I work which is 15 mi or so away postcodes, gl5 and gl51. Can anyone help? Because I'm on the verge of having to have a second phone it is so bad.