I'm sorry if this is the wrong sub but I'm a frequent lurker and feel I would get the best advice from here.

I've put a TL;DR at the bottom for anyone that hasn't got the time to read the below.

I first need to give yourselves a bit of context of the situation I am in.

I have been working for quite a large company for just under 12 months. The company I work for handles other companies facilities like cleaning, maintenance, etc. The low level employees (like myself) that work for my company, work on individual help desks for each companies facilities that we manage. For example (these aren't actual companies we handle) we would have a help desk for Greggs to report jobs to, one for Goldsmith's to report to, one for TUI to report to etc.

During my time here I have worked on 2 different help desk's, one which was a lot busier than the other. I currently work on the one that isn't as busy.

Over the past month or so a lot of redundancies have taken place due to the companies we manage going to the competition to handle their facilities. Due to this the work load for the help desks that still exist has increased exponentially except mine.

This is where I need the advice. Firstly my manager asked me to handle the overflow of calls for the old help desk I used to work on. At first I didn't have a problem with this as there weren't that many. Then my manager asked me to start handling the overflow of calls for other help desks when their workload was full, again didn't mind because it wasn't that often.

I have now been asked to lend a hand where I can on the emails the old help desk I used to work on and this has increased my daily work load massively.

I feel like I am been taken advantage of because my help desk isn't so busy and I have experience from other help desks and feel like I should be compensated for it. I also feel like this is just the start of it and slowly I will be asked to be the 'back up' for other help desks to handle their overflow as well, even if it's just to take messages and pass them on.

However I am not sure if I am in the right to request compensation for it and instead should I just be a 'team player' and help out where needed?

TL;DR Currently work on a help desk that isn't busy. Manager has given me extra responsibilities like overflow calls and emails for other help desks to handle without compensation. I feel like I should be compensated for it but I'm not sure.

Any help or advice would be greatly appreciated.