Are you sending long messages or including emoticons etc which could be converting the text to a mms.
As a process of elimination can you insert your sim card in another phone and try send a text message then ?
Check that neither you or your Dad has added numbers to a blocking facility in the phone.
To add a sim swap can occasionally take 24 hours to fully settle.
Manually choose another network in the phone and then re choose Vodafone.
Put the phone in airplane mode and back off to refresh things.
Current Phone >
Samsung Galaxy s²⁴ Ultra 512gb.
