abra wallet support must give the private key of my bsv wallet address?
Exactly. If you have the private key, you can get the access of your BTC easily with Electrum through importing the private key.
They are indeed compatible. Remove the first word 'at' from the 13 word phrase and enter the remaining 12 words
Missed that. That's why I was confused because I guess the word at is not seed word I have seen ever on Electrum.