Like all spam, it is to advertise. Those numbers could be connected to the scam phone calls that say "your computer is throwing errors and they have called to help you fix it.”
Most of those posts are gibberish, and I got rid of many this morning, and now over a hundred more tonight.********Correction
Make that over 200 posts deleted due to spammers. Some of them are for (insert company name) email support... And yes, all are the same phone numbers - or very close to the same.