How about erased, obliterated, destroyed, or ruined?
"My hard work is always [erased, obliterated, destroyed, or
ruined] by client's repetitive changes. Other employees' hard work is visible to you, but not mine. So everyone here got increment in the
last 7 months but not me."
erase: to obliterate
obliterate: to remove or destroy all traces of; do away with; destroy completely.
destroy: to reduce (an object) to useless fragments, a useless form, or remains, to render ineffective or useless; nullify;
ruin: to injure (a thing) irretrievably
As to the lack of an "increment" compared to other employees, perhaps their work is not washed away, erased, obliterated, destroyed, or ruined by client's repetitive changes to the same extent as is the OP's.