iphone cannot make or receive calls or access mobile data

Ever since my most current update my iphone has had a problem where almost every day sometimes multiple times a day the phone will alert me to the fact it cannot make or receive calls or access mobile data.

i can reset this by turning the phone off and on again, but its starting to give me the ***** and i shouldn't have to reset my phone anytime i want to make a call or access my emails or the internet.

Has anyone else experienced this problem? if you have a fix please let me know because this is making running my small business much harder than it should be.

I have an iphone 7 btw, thanks everyone.

David.