I am sorry to hear you are having issues.
There are many reasons that gel polish can lift: Poor prep, hormonal, medication clients may be on, clients being hard on their nails not wearing gloves when gardening and cleaning, not using cuticle oil etc.
Its hard to pin point what it could be.
If you are sure its not your prep then there is nothing I can suggest.
My daughter tried gel polish when she was 15 and it would start coming off within a few days, my nieces around the same age were the same. I put it down to hormones with them.
I dont use the ibd JGP base coat anymore but when I did I always used the powerbond, just like you said.
Maybe you could try a different base coat and top coat and see if that helps. I now use the Shellac base coat and Shellac Xpress5 top coat with the ibd JGP and it works just fine.
I am sorry I could not be of more help.