A late payment would not increase the loyalty reward period of time beyond each 12 months. As already mentioned by @Yummy that only increases if you have been suspended for 60 days or more. You should see the loyalty $1 amount increase show on in your rewards account after day 361 in your first year after day 722 in your second year and so on.....
Login to your rewards account to check your loyalty amount or you can look at your upcoming bill payment on the payment page in your self-serve account and it will reflect what your loyalty reward currently stands at.
Months that you don't pay will inceease fhe amount of time for loyalty rewards to go up. On the old rewards program, the maximum is $5 per 30 days. If the reason that you reward didn't go up was because of skipped payments, there isn't any reason to contact a customer support agent.
@WilliamDong hi if you are on the olld rewards program after the 1st year you will begin getting 1 dollar per month if you missed any months because of non payment during that time you will not be credited for those months,if on the new rewards program you don;t recieve loalty every cycle only 10 points each year of service