dilema w a mulch job- HELP!!!!

[LawnPatrolNY]

hey everyone, thanks for reading and helping in advance. i have been reading posts for weeks now and finally signed up for an account on here. you guys are great!! so this being my first post i have a dilema. GO EASY ON ME PLEASE

I took on my first mulch job and shrub trim, and i think i quoted way to low after reading what people charge. i quoted "about $200 plus materials", but also told him depends on how long it takes to clear the beds and how many hrs i put in ... so after clearing the beds and putting in about 5 hours of prep work i layed 2 yards of mulch. totaling about 6 hrs of work.

i had my helper @ $10/per hr, cut the shrubs took him about 5 hrs to do that and clean it up (yea i wasnt to happy bout that)

during this time the client also added on to clean up the side of the house that had old logs that were deteriorating and causing a mess, and also mentioned 1 more shrub to be trimmed (about 45 mins of work)

so basically i quoted to low, but like i said i did tell him "depends on how many hrs i put in", so my question is what do i tell this guy, i do have a weekly mow service w him as well, and i dont want him to think that im trying to scam him, and lose his business all together, but i really just thought it wouldnt take me as long as it did. after reading some people and what they charge , its seems like i should have charged about 500 plus material... i dont think i could go and tell this guy that he owes me like $600 now , so what do you think the fairest way to go about this is and what should i charge .

ive also noticed that people haev put comments about typing or spelling, well guess what im typing on the computer and this isnt a proper document so there will be errors and u will just have to deal w it . thanks