Cell phone issues Huawei nova 9

I took a contract with Telekom last year 2022 January with a phone of Huawei nova 9. So recently I have been experiencing issues were my messages does not Update same time, I receive today's messages the following day. So I went to Protea glen store were I was told they can't assist me, I rather buy a new phone this is a contract phone that I'm still paying I need assistance urgently