Serious help needed...

So we had an electrician over. He has my number due to him having to call before coming over to fix the electrical box... He and I chit chatted while he worked. Now that the job is done he's texting me wanting to hang out and talk more... It makes me uncomfortable because one its unprofessional, two I'm not interested and three just no... However I am not a mean person and don't know how or what to reply without sounding like a total B... I'm married and no way interested in another man and this whole situation is just making me feel uneasy.. What do I do.... I have never been in this situation before...