I wrote a little script for sending multiple messages in a single command. Go to https://pastebin.com and paste a series of up to 6 texts separated by backticks. The first text must be up to 200 characters. Subsequent texts must be up to 400 characters. See https://pastebin.com/GUZcy5tP for an example. Then paste the raw paste url into the following command response:
$(urlfetch https://rokbot.xyz/smm.php?msg=$(urlfetch json https://pastebin.com/raw/FOOrBARj))