The most unrealistic part of the time-leap machine is that they had to decompress that 36-byte message and put it back to one's head. And they just used a cellphone for that.
Regarding to compressing a huge amount of data to a 36-byte (288-bit) message - yes, it's totally possible. However there should be a decompressor which would also use a huge amount of data.
Using a black hole for "compression"? It's a joke. Actual compression doesn't work like this. It's all about making tables or "dictionaries". Here's a simple algorithm which can compress any amount of data to a 1-byte message (sometimes it can not):
Compressor: replace "apple" with "1", "orange" with "2", anything else with "3:anything else".
Decompressor: replace "1" with "apple", "2" with "orange", message like "3:anything else" with anything else.
See? It can compress 5-byte and 6-byte messages to a 1-byte message!