The employee definitely should have been able to come to the same conclusion I did, but you got lucky enough to get an employee who either wasn't smart enough or didn't care enough to figure it out. I think Mediacom is terrible for several reasons, but in this case, the bill isn't one of them. The bill for $18.32 that you got credited was for the activation fee and the difference between the estimate and the actual charges.

It seems you were given an estimate of what that first bill would be, so you paid that amount. This usually results in the first bill showing two full months, plus whatever amount of time you had service before the arbitrary billing month start date.

Mediacom ALWAYS bills the next month in full. Add to that the $10 activation fee, and there's the 'mysterious' $18.32 charge. For whatever reason, this was not enough for the charges - $4.51 for two days, plus $96.64 for (roughly) September and October, for a total of $101.15, like it says on the bill. Looks like you ordered service on August 20, and made an advance payment of $92.83. Yes, fuck Mediacom, but this bill makes perfect sense, and the total due is easily accounted for by basic math.

Mediacom bill pay