help! what is prima facia case of libel?

can anyone please help me, some-one is threating to take me to court over prima facia case of libel, i dont know what this is.
it started bcause i questioned about roof repairs on the flats i live in,as there was no notice given about these repairs and we were told to pay the cost, they said he inspected and said it was 100%, information was that he was an author, so i asked to see copies of the bill, qualification of the roofers(as was suggested that the gardners do the repairs!!), plus i said that would be interested to see his qualification for assessing the roof bearing in mind i far as i was aware he was an author.
he sent back a letter showing that he has qualification in roofing and i replied to him saying i was supprised but glad to see he was capable of doing so.
he says he will take me to court with a prima facia case of libel, and i have no idea what this is and at no time did i mean to cause any trouble

He cannot do that. There is no case there. And he was not damaged in any public way.

thank you, but still not sure as i sent the letter to the dirctors of ourflat management company as all flat owners are shareholders of this company plus each flat ahd a copy of the letter, i never said he was not caple but i just was interested in his qualications would this change how the case if viewed??