I'd interpret that as their parts-changers (who like to call themselves "technicians") don't have the knowledge or skills to work on your car.

Clearly they don't want your business. I'd take it elsewhere to someone who does.

__________________
Current stable:
1995 E320 149K (Nancy)
1983 500SL 120K (SLoL)

Black Sheep:
1985 524TD 167K (TotalDumpster™)

Gone but not forgotten:
1986 300SDL (RIP)
1991 350SD
1991 560SEL
1990 560SEL
1986 500SEL Euro (Rusted to nothing at 47K!)