Can my employer require me to pay for a visa agent for my non-B visa renewal in Thailand?

So I basically have a non-B visa with work permit. I reminded my company a month in advance that I need the documents to extend my visa. But they delayed a lot as I am the first foreigner in the company and they do not know the procedures. I now have about a week to get my visa extended.

They are still trying to go through the normal route without a visa agent and I think they have the necessary documentations already. But they said that if the immigration officer requests for any additional documents, we may need to pay for a visa agent. They company expects me to pay for this. Is this normal? I feel like I would be paying for their mistakes as I reminded them a month in advance.

And what are the documents that are needed? Is it possible to get the visa extended within a week? O