Getting AltSoftSerial to work with the Fona 3g

I recently started a project which interacts an accelerometer (I2C) with a Fona 3g gps module. I cannot get them to work together and its driving me crazy! Using the SoftwareSerial library, I was not able to get values from the accelerometer while the gps module was running. I did some online research and found the AltSoftSerial library. this library looks like the solution to my problem but I am unable to find the Fona. I’ve connected the RX and TX pins to digital 8 and 9 respectively on the Nano but its not working. My accelerometer is connected to digital pins 10 and 12 on the Arduino (SDA and SCL respectively). I am aware that the AltSoftSerial disables the PWM on pin 10 but I don’t think that should make a difference.
things to note:
The accelerometer and gps module were working fine independently (when I was using SoftwareSerial with pins 7 and 8 for RX and TX)
I am using the Adafruit ‘FONATest’ code to troubleshoot.
any help is greatly appreciated.

FONAtest.ino (24.6 KB)

My accelerometer is connected to digital pins 10 and 12 on the Arduino (SDA and SCL respectively).

SDA/SCL are not on pin 10/12 on the Nano!

Using the SoftwareSerial library, I was not able to get values from the accelerometer while the gps module was running.

Which SoftwareSerial version are you using? With a current IDE version SoftwareSerial isn't blocking as much as in earlier versions, so it should work if you use the hardware I2C interface (see above).