Getting money from ex

[Fuzzyduckduckyfuzz]

Ex and I split 10 months ago with him owing me 6000 pounds plus his phone bill each month. I’ve been reasonable during lockdown and only taken his phone bill money but I now know he is working and therefore should be paying me more. I have it in writing him admitting what he owes me and also have proof that I paid for his car.

Is it worth going to a solicitor to sort this out? He has now blocked me - ironically when I own and pay for his phone

You don't need a solicitor for this. The small claims court deals with debts of up to £10,000 assuming you are in England or Wales. Send him a letter setting out a summary of why he owes you money, giving him a reasonable deadline to pay and saying you will take legal action if he fails to do so. If he still fails to pay you can then start a claim.