Homepage loading with questions marks within diamonds and random text

Hi there

My site until recently was working fine if not running a little slow which I had my hosting company look at the issue. They requested to access the website through wordpress and ever since then the site has shown text like this when loaded:

??}?r?H??s+??PCo4??@?D???? ???CR??x (??A ??4?????????p>b??dV??+(?c?I?[“???????UU??_N??λk??N?o^]4?$#??oK?|??sJ?v?? b?@:?l8????????U?d?k??????rw??i??V?a?X??(???9?U3’Ov??”D$???Y??C?p?g???*?!?l?3?n?b???g??K?U3?VnH.

When I access the site to edit it looks fine and as it should.

Any suggestions as to what is going on?

Website is https://www.sust-insight.com