Getting Error 500 when texting from my phone also unable to make calls or receive calls

[splash2]

Hi I'm using a huawei P20 pro and just recently as in today it has stopped texting from the phone reporting error 500 and also phone calls show up as having called but only last 1 sec and unable to make calls. Internet also is flaky or just does not work. This is a work provide sim so I assume that the bill has been paid.

[KDS_software]

1) Reset network settings on phone

2) If doesnt work try the sim in another phone.

3) if still nothing get the listed authority on the business account to organise a sim swap.