If she goes on the oman run with GO TOURS you need to pay a fee to cover the transport ( there and back of 150 EAD and then 50 for the visa) all safe and not that bad- and then the visa is in your passport. Yes it takes few hours out of your day but the easiest way to do it .
good luck
Did she had her first visa by an tourist company, so not a stamp on arrival visa? Then you can't see the renewal as this is something in the system only.
However you say visa renew by Oman, that should mean there is a new stamp in her passport?
How can you know if a visa was extended? a friend had a tourist visa of 40days, she was looking for a job, she came in the country 18th of September and exited for visa change on 30th Oct to Oman after requesting the agent to give a copy of extended visa in vain. The agent is insisting for extension fee but she has not received a copy of extended visa. How can she go around with this?