U gain reputation whenever someone click on thanks button on ur thread or click on rep button "small scale icon" to grant you reputations.

U earn credits whenever u post a reply or start a new thread.

Both reps and credit can be decreased by mods, if you are not following the rulez, which btw in ur case are multiple replies when one was needed. for example, above replies from Vish, in this case he posted a reply then tot something else and wanted to add, all he need to do is click edit to his original reply and just add or delete watever he wished. Posting multiple replies will eventually cause us to minus ur credits so in the end u dun earn any credits and also risk of getting an infraction for spamming. Now lets say someone replies to ur reply, in this case again for example, Vish replied to ur original post, u then reply to wish by posting a brand new reply, that doesn't conside spam as ur posting a reply to someone. Or in case when we have a discussion thread obviously u wont gonna keep editing ur original post u will keep replying anew and thus posting new replies.
Basically if its feasible edit ur original post to put all ur updates other wise reply.

Plz feel free to ask any mods if u have any qts we r here to help.