CELL C

We have very low signal at our offices we have reported the problem with all 7 numbers to Cell C they have sent a tech out who categorically told us IPHONE on CELL C is a problem , they are having countless issues and we should get new software on our phones ! we all have Iphone 11 Pro brand new phones and Iphone X also relatively new phones , she the tech then proceeded to test the data speed which was 0,03 Mbps and said that's great and we must contact apple to upgrade our phones i am at my end here !!!!! should i contact the CPA ? we cannot run a business like this