Yes, since you are from US, there is the FIFO regulation. Which means that you can not trade more than one EA per currency pair.
Now there was a discussion about that in the Forum. Some students shared they can trade but with different lots. For example, if you have 3 EAs on EURUSD, one can be with 0.1 lots, the other one with 1.11 lots, and the third one with 0.12 lots. Or any similar combination.
Also, there are some brokers that allow US clients. Maybe some of the students from there can share it.
Cheers,
P.S they wrote to you about the number of trade, not the number of EA. Each trade, no matter how you opened – manually or automatically, has a number.