easy, you say: throughout the 7 years we've been together we have communicated everyday (or how often) by these means (list the ways you communicated). things we talked about were: family life, vacation time, work life, missing eachother, our future, etc.
where does it say in the application you need to show "continuous communication" by submitting social media or phone messages? it doesn't. i'd recommend not sending any, and just referencing the ways you communicated in your answers. you are over thinking the application and you will end up making your case more complicated if you try to overload the application with this stuff. LESS IS MORE. QUALITY OVER QUANTITY.