いけないて isn't valid - use いけなくて instead. Also, on a side node, assuming that this is a situation where you're rejecting someone's invitation to meet up in the weekend you could replace 「都合が悪い」 by 「次の週末はちょっと...」 to make it less explicit and thereby more polite.
Thanks, I knew about なくて, it was my typo. It's not really a rejection to an invitation. I have weekly chats with a girl from Japan and I want to say that this weekend I won't be able to make it, for those reasons. But I guess that ちょっと would be good in that situation too. Thanks for the advice.
In that case, if she didn't ask you for a chat next weekend but you're just informing her on your own initiative, I wouldn't use ちょっと. Instead use the original and maybe add something about how you're still looking forward to the weekend after that