Hi @Goodlifer,
Welcome to our community forums and thank you for your first post.
Sorry to hear you are having issues when making calls, we can understand this is not ideal and we want to best help. Just to clarify, what do you experience when you mean crossed lines? Do you hear another line in the background? Is the line noisy? Also, you may find the following link useful https://www.virginmedia.com/shop/mobile/sim-help
Please get back to us when you can.
Thanks,